How do I invoice clients and send automatic reminders in the US?

Invoicing clients in the US: the practical, repeatable system

Invoicing sounds simple—send a bill, get paid—but in the United States the details matter. Your clients expect professional documents, clear payment terms, and predictable follow-ups. You also want your invoicing process to be fast, consistent, and compliant with common business expectations across industries. The good news is that you don’t need a complicated accounting department to invoice like a pro. You need a reliable workflow: gather the right client details, set terms, create clear invoices, send them using a consistent cadence, accept easy payment methods, and automate reminders without sounding aggressive.

This article walks you through exactly how to invoice clients and send automatic payment reminders in the US—whether you’re a freelancer, consultant, agency, contractor, or small business. You’ll also learn best practices for deposit requests, late fees, sales tax, W-9s and 1099s, and how to create an email reminder sequence that improves collections while preserving client relationships. If you use invoice24, you can implement every step described here using one app: creating invoices, customizing templates, setting payment terms, accepting payments, tracking status, and sending automated reminders.

Step 1: Decide what “getting paid on time” means for your business

Before you write your first invoice, define your payment policy. Many payment issues happen because the expectations weren’t clear. “Net 30” means payment is due 30 days after the invoice date. “Due on receipt” means the due date is the same day the invoice is issued. “Net 15” is common for smaller projects. For retainers or ongoing services, monthly invoicing on a set date is typical. For project work, milestone billing (e.g., 40% upfront, 30% mid-project, 30% on completion) reduces risk and smooths cash flow.

Pick policies you can apply consistently. A consistent policy makes you easier to work with and reduces awkward negotiations. If you’re frequently waiting for payment, you’re effectively financing your clients. It’s reasonable to ask for a deposit, request payment upfront for smaller engagements, or require a payment method on file for recurring billing. Your goal is not to be strict for the sake of strictness; it’s to make payment predictable for both sides.

Step 2: Collect client details you’ll need on every invoice

To invoice US clients smoothly, gather a core set of information during onboarding. At a minimum, you want the legal business name (or the person’s name for individuals), billing email address, billing address, and the name of the person who approves payments (accounts payable contact). If they are a larger organization, they may require a purchase order (PO) number, vendor ID, or specific invoice formatting. If you don’t ask upfront, you may learn about these requirements only after an invoice is rejected.

Here’s a practical checklist of what to collect:

• Client legal name and DBA (if applicable)
• Billing address (street, city, state, ZIP)
• Billing email (and backup contact)
• Accounts payable contact name and phone (optional but helpful)
• Any PO number, vendor ID, or required reference codes
• Preferred delivery method (email, portal upload, EDI, etc.)
• Payment method preferences (ACH, card, check)
• Tax-related information relevant to your work (sales tax exemption certificates, if applicable)

With invoice24, you can store client profiles so these details automatically populate future invoices and reminders, reducing admin work and mistakes.

Step 3: Understand what a US invoice should include

In the United States, an invoice isn’t a government-mandated format for most small businesses, but it does need to be complete and unambiguous. A clear invoice reduces back-and-forth and shortens the time between “sent” and “paid.” In general, your invoice should answer five questions: Who is billing? Who is being billed? What is being billed? How much is owed? When and how should it be paid?

Most professional invoices include:

• Your business name, address, phone, and email
• Your logo (optional but professional)
• The client’s billing name and address
• Invoice number (unique and sequential is best)
• Invoice date and due date
• Itemized products/services (description, quantity/hours, rate, line total)
• Subtotal, discounts (if any), taxes (if any), and total due
• Payment instructions (link, bank details for ACH, mailing address for checks)
• Notes and terms (late fee policy, refund policy, scope references)
• Any required references (PO number, project code, contract number)

Invoice numbers matter more than many people realize. They help your client’s accounting team file payments correctly and help you reconcile income. A simple system is fine: INV-0001, INV-0002, etc., or year-based numbering like 2026-001. The key is uniqueness and consistency.

Step 4: Choose payment terms that match how your clients operate

Payment terms are both a due date and a set of expectations. Many corporate clients run payments on fixed cycles—often weekly or twice per month. If you issue an invoice right after they’ve closed a payment run, it might not get paid until the next cycle. That doesn’t mean you should accept long delays, but it does mean you should plan around reality. If you’re a freelancer working with small businesses, “Net 7” or “Net 15” can be reasonable. If you serve larger companies, “Net 30” might be standard, but you can still request deposits or milestone payments.

Common US terms include:

• Due on receipt: best for small, fast projects and new clients
• Net 7 / Net 14 / Net 15: common for service businesses with shorter cycles
• Net 30: common for agencies, B2B vendors, and corporate clients
• Net 45 / Net 60: sometimes requested by large organizations; consider pricing accordingly

If a client insists on longer terms, you have options: charge a premium, request a deposit, invoice more frequently, or offer an early payment discount (for example, 2% off if paid within 10 days). A small discount can sometimes be cheaper than waiting an extra month for cash.

Step 5: Decide whether to request deposits or retainers

Deposits and retainers are common in the US, especially for creative services, contracting, consulting, events, and custom work. A deposit reduces your risk and improves cash flow. A retainer creates stability for both sides and often includes a set number of hours or deliverables each month.

Examples of common approaches:

• 50% deposit upfront, 50% due on completion (simple and widely used)
• Milestone billing for longer projects (e.g., 30% / 40% / 30%)
• Monthly retainer billed in advance (e.g., “February retainer due Feb 1”)
• “Payment required to schedule” for appointments or bookings

When invoicing a deposit, label it clearly (“Deposit for Website Redesign – Phase 1”) and explain how it is applied to the final balance. If you use invoice24, you can create partial invoices or separate invoices for deposits and milestone payments while keeping everything tied to the same client and project notes.

Step 6: Handle sales tax the right way (without overcomplicating it)

Sales tax in the US is state-based and can be complicated, especially for digital products and services. Whether you need to charge sales tax depends on what you sell, where you have tax obligations, and where your customer is located. Many service-based businesses do not charge sales tax on most professional services, but there are exceptions. Some states tax certain services, and product sales generally involve sales tax if you have nexus.

The practical takeaway: don’t guess. Establish whether your business should be collecting sales tax and in which states. If sales tax applies, your invoice should show the tax rate and amount as a separate line item, and you should label the tax clearly. If your client is tax-exempt (common for nonprofits or resellers), collect their exemption certificate and keep it on file.

Invoice24 can help by letting you add taxes as line items or as invoice-level taxes, making sure totals calculate correctly and that the invoice remains easy for your client to review.

Step 7: Build an invoice template that looks professional and is easy to pay

A great invoice is easy to scan. Many clients approve invoices quickly when they can see the essential details in seconds: total due, due date, what it’s for, and how to pay. Use clear labels, avoid overly creative formatting, and keep descriptions specific. “Design work” is vague; “Homepage layout design (6 hours)” is better. If your work relates to a contract or statement of work, reference it: “Per SOW dated Jan 10, 2026.”

Consider adding:

• A short “Thank you” note (friendly but not distracting)
• A one-line summary of what was delivered
• Payment options and a “Pay Now” button/link if you accept online payments
• Your business tax ID or EIN only if appropriate for your context (many invoices do not require it)

Template consistency matters. When your invoices look the same each time, clients learn where to find the key details. Invoice24 lets you set a default template, logo, colors, and terms so each invoice stays consistent without extra work.

Step 8: Send invoices at the right time (timing is a collection strategy)

Sending invoices promptly is one of the most overlooked ways to improve cash flow. If you wait until the end of the month to invoice for work done early in the month, you add weeks of unnecessary delay. Send invoices as soon as a milestone is approved, the project ends, or the billing period closes.

Common timing approaches:

• Upon delivery: invoice immediately when work is delivered and approved
• Weekly: ideal for contractors tracking hours
• Biweekly: matches many payroll cycles for contract work
• Monthly: standard for retainers and ongoing services, usually invoiced at the start of the month (in advance) or at month-end (in arrears)

If your client has a formal accounts payable process, ask about their cutoffs: “When do you need invoices submitted to be included in the next payment run?” This one question can reduce late payments without any reminders at all.

Step 9: Make payment easy: the fastest way to reduce late invoices

Clients pay faster when it’s convenient. In the US, the most common business payment methods are credit/debit card, ACH bank transfer, and checks (still surprisingly common for B2B). Some larger businesses prefer ACH or bill pay. If you only accept checks, you’ll often wait longer. If you only accept cards, some clients will push back due to internal policies or card limits. Offering at least two options is a strong baseline.

To make payment easy, include:

• A clear payment link for card/ACH (if you accept online payments)
• ACH instructions (bank name, routing number, account number, account type), presented clearly
• Check mailing address (if checks are accepted)
• A short “Payment memo” suggestion (e.g., “Include invoice number INV-0102 in memo”)

Invoice24 helps by centralizing payment instructions, so you don’t have to rewrite them each time, and by tracking invoice status so you can see what’s outstanding at a glance.

Step 10: Track invoice status like a system, not a memory game

Once you send an invoice, your job isn’t finished. You need a simple way to track what’s been sent, viewed, paid, or is overdue. Without tracking, you end up searching email threads, guessing due dates, or forgetting to follow up. That’s how invoices slip through the cracks for both you and your client.

A practical invoice pipeline looks like this:

• Draft: invoice created but not sent
• Sent: delivered to client
• Viewed (optional): client has opened it
• Due soon: approaching due date
• Overdue: past due date
• Paid: settled in full
• Partially paid (optional): deposits or partial payments recorded

In invoice24, these statuses can be tracked within your dashboard, so you can filter overdue invoices and trigger reminders automatically instead of manually searching.

Automatic reminders: why they work (and why clients don’t mind them)

Many business owners avoid reminders because they feel awkward. But in practice, clients are used to them. Accounts payable teams manage many vendors, and a polite reminder is often helpful. Most late invoices aren’t malicious; they’re forgotten, stuck in an approval queue, missing a PO number, or waiting for the next payment run. A well-written reminder sequence saves you time and helps the client act faster.

Automatic reminders work best when they are:

• Polite and matter-of-fact (no guilt trips)
• Timed around due dates (before and after)
• Specific (invoice number, amount, due date, link)
• Easy to act on (payment link and contact method included)

Step 11: Set up a reminder schedule that fits US business norms

A strong reminder schedule begins before the due date and continues after, with increasing firmness while remaining professional. Here is a commonly effective cadence for US clients:

• Reminder 1: 7 days before due date (“Friendly reminder”)
• Reminder 2: 1 day before due date (“Due tomorrow”)
• Reminder 3: 3 days after due date (“Overdue”)
• Reminder 4: 7 days after due date (“Second notice”)
• Reminder 5: 14 days after due date (“Past due – please advise”)
• Reminder 6: 21–30 days after due date (“Final notice / next steps”)

This cadence works because it catches invoices that are about to be forgotten, it prompts action right after the due date, and it keeps the invoice visible in inboxes without overwhelming the client. For smaller invoices or long-standing clients, you can reduce the number of reminders. For larger invoices, you may want to add a personal outreach step earlier (for example, a call at 7–10 days overdue).

With invoice24, you can automate this sequence so reminders send based on the invoice’s due date and status. Once it’s set, the app handles the timing and stops reminders when the invoice is paid.

Step 12: Write reminder emails that are firm, friendly, and effective

Reminder tone matters. You want to sound professional and calm. The best reminder emails feel like a routine business process, not an emotional confrontation. They should include the invoice number, amount, due date, and a direct link to view and pay. They should also invite the client to respond if there’s an issue, because issues are common: incorrect billing address, missing PO number, a dispute about scope, or a payment method limitation.

Use a simple structure:

• Subject line that includes invoice number and status
• One short opening sentence
• The essential details in one place
• A clear call to action (pay now / confirm payment date)
• A polite closing and signature

Examples of subject lines that perform well:

• “Reminder: Invoice INV-1042 due on Feb 5”
• “Invoice INV-1042 is now due”
• “Past due: Invoice INV-1042 ($1,250)”

Invoice24 lets you customize reminder templates so your brand voice stays consistent, and so the details (invoice number, due date, total) auto-fill correctly every time.

Step 13: Use late fees carefully (and only when you’re willing to enforce them)

Late fees can encourage timely payment, but they can also irritate good clients if applied unexpectedly. The key is transparency. If you plan to charge late fees, include the policy in your invoice terms and ideally in your agreement or proposal as well. A common approach is a percentage per month (for example, 1.5% per month) or a flat fee after a grace period. Some states have rules about maximum interest rates or how fees must be disclosed, so keep your policy reasonable and well-documented.

A practical approach that balances firmness and relationships:

• Include late fee language in terms
• Offer a short grace period (3–5 days)
• Apply fees consistently for chronic late payers
• Waive fees occasionally for strong clients who had a one-off issue

Even if you don’t charge late fees, you can mention next steps in later reminders, such as pausing future work until the account is current.

Step 14: Know when to switch from automation to a human follow-up

Automation is excellent for routine follow-ups. But when an invoice becomes meaningfully overdue, a direct message can resolve issues faster. Consider personal outreach when:

• The invoice is more than 10–14 days overdue
• The amount is large relative to your business cash flow
• The client has a history of late payments
• You suspect the invoice is stuck in approvals or missing information

When you follow up personally, keep it professional: ask if they received the invoice, confirm whether a PO number is required, and ask when you can expect payment. If the client says “we’ll pay next Friday,” note the date and follow up if it doesn’t happen. Your goal is clarity, not confrontation.

Step 15: Prevent payment delays with better upfront process

The best reminder is the one you never have to send. Many late payments can be prevented by tightening a few steps at the beginning:

• Require a signed agreement before work starts
• Collect a deposit for new clients or large projects
• Ask for PO numbers and billing requirements upfront
• Send invoices immediately after milestones, not weeks later
• Make payment options easy and visible
• Keep invoice descriptions clear and match the client’s internal language

For example, if your client budgets by department, include a department name or project code in the invoice notes. If they require vendor onboarding, complete it early rather than after the first invoice is due.

Step 16: Handle partial payments, credits, and adjustments cleanly

Sometimes clients pay part of an invoice (especially when deposits are involved) or request adjustments due to scope changes. The key is to keep the record clear so neither side gets confused later. If you accept partial payments, track the remaining balance and update the invoice status accordingly. If you issue a credit, document it clearly with a credit note or an adjustment line item so your totals remain accurate.

Good practices include:

• Use separate line items for discounts or credits instead of editing history invisibly
• Reference the reason for the adjustment (e.g., “Scope change – removed deliverable X”)
• Keep communication in writing for clarity
• Confirm the new total and due date after adjustments

Invoice24 helps by keeping an organized audit trail—what was invoiced, what was paid, what remains, and any notes that explain changes.

Step 17: Invoicing contractors and B2B clients: W-9s and 1099 expectations

If you provide services as an independent contractor in the US, some clients may request a completed W-9 form. This form gives them your name, business entity type, and taxpayer identification number so they can issue a 1099 form at year-end if required. This isn’t part of the invoice itself, but it’s part of the broader payment ecosystem for US businesses.

Practical tips:

• Provide your W-9 when asked, especially for new vendor onboarding
• Keep your business name consistent across invoices and W-9s
• If you change business entity type or address, update clients early

Not every client will ask, and not every payment triggers a 1099 obligation, but being prepared reduces friction and speeds up approval.

Step 18: Create clear terms and include them in every invoice

Terms should be readable. A wall of legal text at the bottom of an invoice rarely helps. Instead, include short, plain-language terms that cover the issues most likely to matter: due date, late payment expectations, what happens if payment is delayed, and how to contact you.

Example terms you can adapt for your business style:

• “Payment is due within 15 days of invoice date.”
• “Please include the invoice number with your payment.”
• “Work may be paused on accounts more than 14 days past due.”
• “If you have any questions about this invoice, reply to this email.”

For service businesses, it can also help to clarify that the invoice reflects delivered work and that any disputes should be raised within a certain window (for example, 7 days). That encourages faster review and reduces surprises later.

Step 19: Keep your invoicing workflow consistent from quote to payment

Invoicing gets easier when it’s the final step in a consistent workflow: quote → agreement → work → invoice → reminder → payment → receipt. If you skip steps, invoicing becomes a scramble. Even a simple checklist can help you maintain consistency:

• Confirm scope and price in writing
• Confirm billing contact and PO requirements
• Decide on deposit/milestone schedule
• Deliver work and get approval (or confirm time period completed)
• Generate invoice with itemized details and terms
• Send invoice and confirm receipt for first-time clients
• Let automated reminders handle routine follow-ups
• Record payment and send a receipt/confirmation

Invoice24 supports this approach by keeping client information, invoices, statuses, and reminders in one place, so you don’t have to build a patchwork system across spreadsheets and email threads.

Step 20: What to do when clients still don’t pay

Even with a strong system, some invoices become seriously overdue. When that happens, escalation should be structured and professional. The goal is to get paid while minimizing time spent and avoiding unnecessary conflict.

A practical escalation ladder:

• 7 days overdue: automated reminders + a quick personal check-in
• 14 days overdue: ask for a firm payment date; pause new work if appropriate
• 21–30 days overdue: send a “final notice” style email stating next steps
• 30+ days overdue: consider collections options (depending on amount and relationship), or small claims court for smaller balances where appropriate

Before escalating, confirm the invoice is correct: correct billing entity, correct email, correct PO number, correct description. Many “non-payment” situations are actually process failures. If the client is responsive but slow, work with them on a payment plan. If they are unresponsive, keep communications concise and documented.

Common invoicing mistakes (and how to avoid them)

Here are the most common reasons invoices get paid late, along with fixes you can implement immediately:

• Vague descriptions: Use specific line items and reference the project or period.
• No due date: Always include a due date, not just “Net 30.”
• Missing PO number: Ask for it upfront and include it on the invoice.
• Hard-to-pay invoices: Offer easy payment options and include a payment link.
• Inconsistent follow-up: Use automatic reminders tied to due dates.
• Sending invoices to the wrong person: Confirm accounts payable contact details.
• Waiting too long to invoice: Invoice immediately after delivery or on a fixed schedule.

When you build invoicing as a routine process, you reduce mistakes, reduce stress, and shorten your payment cycle. That’s true whether you send five invoices a month or five hundred.

Putting it all together in invoice24

If you want a simple system you can run repeatedly without thinking, set up invoice24 with these defaults:

• Create client profiles with billing contacts and addresses
• Set a default invoice template with your branding and terms
• Choose standard payment terms (e.g., Net 15 or Net 30) and a deposit policy for new projects
• Enable at least two payment methods (for example, card and ACH, or ACH and check instructions)
• Turn on automatic reminders using a proven cadence (before due, on due, and after due)
• Track invoice statuses from sent to paid and review overdue items weekly

This setup makes invoicing feel less like chasing money and more like running an orderly billing operation. Your clients get clear invoices, predictable reminders, and easy payment paths. You get faster payments, fewer awkward emails, and a dashboard that tells you exactly what’s outstanding.

Final checklist: invoice and reminder workflow for US clients

Use this checklist as your repeatable process:

• Confirm client billing details and requirements (including PO number)
• Set payment terms and deposit/milestone schedule
• Create an itemized invoice with invoice number, dates, and payment instructions
• Send the invoice promptly to the correct billing contact
• Automate reminders: 7 days before due, 1 day before due, then 3/7/14 days after due
• Follow up personally when needed for higher balances or longer delays
• Record payment and send confirmation/receipt

When you treat invoicing and reminders as a system, you improve cash flow, reduce administrative work, and build a more professional client experience. Whether you’re just starting or scaling up, invoice24 can help you send invoices that get paid and reminders that keep your revenue predictable.