How to add a watermark to a PDF

The short answer

Drop one or more PDFs into the tool below. Under Watermark choose Text and type your words, or choose Image and select a PNG or JPG logo. Pick a Layout (Diagonal, Centered or Tiled), set Opacity and Size, and optionally limit the Pages, for example 1-3 or 2, 5. Each file is stamped right away and can be downloaded on its own or all together as a ZIP.

The default is a red CONFIDENTIAL across the page diagonal at 25 percent opacity, which suits most internal documents as it is. The tool remembers your last settings on this device, so the next batch looks the same.

Choosing the wording

Short, upper case words read best through body text. Keep the text to one line; long sentences become tiny when they have to fit across the page.

• CONFIDENTIAL or INTERNAL: documents that should stay inside a company or between named parties.
• DRAFT or NOT FINAL: versions sent for review, so nobody signs or prints the wrong one.
• COPY or SAMPLE: copies of certificates, IDs and invoices, or examples sent to clients.
• A recipient line, such as For Example Ltd only, 2026-10-26: if the file leaks, the watermark shows whose copy it was. This is the most useful watermark for protecting sensitive documents.
• Text works in any language and alphabet, including accented letters, Cyrillic, Greek, Arabic and Chinese, because it is drawn with the fonts on your device.

Layout, opacity and size that work

Diagonal runs the watermark from corner to corner and its Size is a share of the page diagonal. Centered places it horizontally in the middle, sized as a share of the page width. Tiled repeats a smaller copy at an angle across the whole page in staggered rows, which is the hardest to crop out.

Opacity decides whether the watermark is a hint or a barrier. Below 10 percent it disappears on many printers; above 40 percent it starts to hide the text underneath. Color matters too: red and gray stay visible on both black text and photos, while light colors vanish on white paper when printed.

Using your logo as a watermark

Choose Image and select a PNG or JPG file. A PNG with a transparent background looks clean; a JPG brings its white or colored box with it, which shows as a faint rectangle on the page. If you only have a JPG, remove the background first with Anyfeat's background remover and save it as PNG.

Use a logo of at least 1000 pixels wide so it stays sharp when it covers a large part of the page. Keep opacity low (10 to 20 percent) for branding, so the content stays easy to read. Note that the logo is always placed in the center or tiled across the page; the tool does not place it in a corner like a letterhead.

What a watermark protects, and what it does not

A watermark is a visible label. It is good at telling readers what a document is and at discouraging casual misuse, but it cannot stop a determined person. It helps to know the limits before relying on it.

• It does: mark the status of a document, make a leaked copy traceable when it names the recipient, make screenshots and printouts carry the label, and make reuse of scanned IDs for other purposes harder.
• It does not: prevent opening, printing or copying. Anyone with the file can read it. For that, the PDF needs a password, which a watermark tool does not add.
• It can be removed: the watermark is drawn on top of each page and someone with a PDF editor can delete it. Tiled watermarks over text are much harder to remove cleanly than a single centered stamp.
• It does not hide what is underneath: the original text is still in the file and can be copied or searched. If something must not be seen, redact it properly instead of covering it.
• It is not a signature: a watermark does not prove who approved a document or that it has not been changed.

Common problems and fixes

• The watermark is hard to see on paper: raise the opacity to 30 to 40 percent or use a darker color. Screens show faint marks better than most office printers.
• The text underneath is hard to read: lower the opacity or the size, or switch from Tiled to Diagonal.
• Only some pages need a mark: type them in the Pages field, for example 2- to leave the cover page clean.
• The tool says to choose a logo first: in Image mode you need to select a PNG or JPG before the files can be stamped.
• The PDF will not open: it is probably password protected. Remove the password in your PDF reader, add the watermark, then protect it again if needed.
• The watermark text cannot be selected or searched: that is expected. It is placed as an image, so it looks the same everywhere and does not mix with the document text when someone copies it.