- Drag it in, choose it, or paste it. It is read here in the tab and never uploaded.
- The settings column holds 14 controls for this tool. The defaults suit most files.
- “Add watermark” works on your device, then Original and Result sit side by side with a download.
About Watermark PDF
Watermark PDF stamps text or an image across the pages you choose — at the position, angle, size, color and opacity you set, once per page or tiled across it.
A watermark is either a word or a picture, stamped once on the page or tiled across it. Everything that decides how it reads is exposed: position, rotation, opacity, size, color, the font, and for a tiled mark the gap across and down. The default — a translucent word at thirty degrees in the middle of the page — is the one everyone recognizes, and the one most likely to get in the way of the text.
Opacity is the setting worth spending time on. Low enough and the mark is a texture nobody reads; high enough and it is a claim over the document but the paragraphs underneath become hard work. A tiled mark at very low opacity is harder to crop out than a single big one, which is the argument for tiling.
The stamp is drawn into the pages you choose, so it is not an annotation a reader can hide or delete. It is still only ink on a page: anyone determined enough can cover it or rebuild the page without it. A watermark marks a document, it does not protect it — that is what Protect is for.