Add watermark to PDF

Text watermarks work well when the message matters more than branding. Australian businesses commonly use “Draft”, “Confidential”, “Sample”, “For review”, “Internal use”, “Paid”, or a client/project reference. Keep the text short enough to read at a glance, then set opacity between about 15% and 35% so the watermark is clear but does not hide the PDF content.

A diagonal watermark across the centre is best for status labels such as DRAFT or CONFIDENTIAL. A corner watermark is better for a reference number, department name, or short distribution note. If the document will be printed, preview the mark on both portrait and landscape pages before exporting.

Use image mode when a company logo, product mark, project logo, or approval stamp should appear across a document. Transparent PNG is usually the cleanest format for a logo because it preserves soft edges and avoids a white box around the artwork. JPEG is fine for photographic marks or simple rectangular graphics.

For most business PDFs, use a smaller logo in a corner or a very low-opacity large logo in the centre. Avoid placing a strong logo over totals, signatures, key terms, compliance notes, or dates. If the PDF has mixed page sizes, check the preview for each size because one scale setting is adapted across the pages.

Not every PDF needs a mark on every page. Put a “DRAFT” mark on the whole file, a “PAID” mark on the first page of an invoice copy, a logo on the cover page, or a confidentiality mark on only the annexures. Custom expressions such as 1-3, 7, 10- are useful for long packs where the cover, schedules and attachments need different treatment.

Tiled watermarks are useful when the mark should remain visible even if a page is cropped or a screenshot is taken. Use tiling for confidential review packs or sample catalogues, and increase spacing if the document feels crowded.

The tool is designed so the PDF bytes stay in your browser. That matters for client files, supplier documents, employee paperwork, board packs, lease documents, strata paperwork, and other PDFs that do not need to pass through a third-party server just to add a visible label.

Browser processing also means practical limits depend on the device. Very large PDFs, very high-resolution scans, or many files at once may use a lot of memory. Process smaller batches if the browser becomes slow, and keep the original files unchanged until you have checked the exported PDFs.

A visible watermark is a warning or label. It can discourage casual reuse, identify a draft, or show who a file was prepared for, but it does not remove sensitive information. To hide information, use proper redaction before sharing. To restrict opening or editing, use password/security settings. To prove signing integrity, use a digital signature workflow.

Adding a watermark changes the PDF. If a PDF is cryptographically signed, editing it will normally invalidate the signature. That is expected behaviour: the signature is meant to reveal that the document changed after signing.

If the watermark is too strong, reduce opacity before changing the colour. If it lands in the wrong place on rotated or landscape pages, use the page preview and offsets rather than assuming every page has the same geometry. If a PDF is encrypted, unlock it first and then add the watermark. If a logo looks boxed in, use a transparent PNG rather than a JPEG with a solid background.