How to add a watermark to a PDF

What a watermark is for

A watermark is text printed faintly across every page, such as DRAFT, CONFIDENTIAL, COPY or SAMPLE. It tells anyone who sees the document, on screen or on paper, how it should be treated.

Watermarks are a label, not a lock. Anyone with a PDF editor can cover or remove them. To stop people from opening a file, use password protection instead, or as well.

How to add one

Open the PDF in the editor, open the tools menu and choose Add Watermark. Type the text, pick a colour and set the opacity, then apply. The watermark is placed diagonally across the centre of every page and the new PDF downloads straight away, including any other edits you made.

Watermarks work in any language, including letters such as æ, ø, å, ł and Cyrillic or Greek text.

Choosing settings that stay readable

Keep the text short. One or two words read clearly across a page; a full sentence becomes small and hard to read.

An opacity of about 20 to 35 percent is usually right: clearly visible, but the document underneath can still be read. Grey or a muted colour is easier on the eye than bright red, and it prints more predictably.

Keep a clean copy

The watermark becomes part of the page content in the downloaded file. Keep the original without a watermark, so you do not have to remove it later when the document is final.