How to Add a Watermark to a PDF (Text or Logo, Free)

To watermark a PDF, place a text or image layer, such as CONFIDENTIAL, DRAFT or your logo, across every page, make it semi-transparent so the content stays readable, and save a new copy. You can do it for free in a browser tool, in Word or Google Docs before you export to PDF, or in paid Adobe Acrobat.

A watermark tells anyone who opens the file what it is and who it belongs to: a draft that is not final, a confidential HR letter, a sample chapter, a photographer's proof, a copy of an ID made for one purpose only. It is quick to add, but the details decide whether it helps. Too faint and nobody notices it; too strong and the page becomes hard to read. This guide covers how to add one step by step, the settings that work for common jobs, and the free alternatives on Windows, Mac and phones.

Key takeaways

• Adobe defines a watermark as "fixed text or an image added to a PDF to indicate ownership, display branding, or mark content as confidential" (Adobe).
• A watermark is a label, not a lock. Pair it with a password from Protect PDF when access matters.
• Siliph's Watermark PDF adds text or a PNG or JPG logo to every page, with opacity, rotation, size and colour controls and a live preview. It is free with no account.
• Word and Google Docs both have a watermark command, so if you still have the source document you can add it there and then export to PDF.
• Around half opacity on a diagonal reads clearly without hiding the text underneath.

What a watermark does and does not do

A watermark discourages misuse and makes the status of a document obvious. It does not stop anyone opening, printing or copying the file, and someone with a full PDF editor can sometimes select and remove it. Treat it as a clear, visible statement.

If the aim is to keep information private, a watermark is the wrong tool. To stop people opening the file, add an open password with Protect PDF; our guide on choosing a strong PDF password explains how. To take account numbers or names out of a document before sharing it, use Redact PDF, which removes the text rather than printing over it.

Pick the wording and settings first

The ID copy case is worth doing well. Writing the purpose and date across a scan of a passport or licence, such as "For tenancy application only, 25 October 2026", makes it harder to reuse that copy for something else. Keep the text short enough to fit the page width, and make sure the photo and the key numbers are still legible.

How to add a watermark to a PDF with Siliph

1. Open Watermark PDF and click Choose a PDF file, or drag it into the drop zone. A file can be up to 150 MB and 2,000 pages.
2. Under Watermark type, choose Text watermark and type your words, or choose Image watermark and add a PNG or JPG logo as a second file after the PDF.
3. For text, pick a Colour and a Font size between 12 and 120 pt. Then set Opacity anywhere from 10% to 100% and Rotation from -90° to 90°. The Live preview updates as you change each setting.
4. Click Add watermark.
5. Download the new PDF and check the busiest page, such as a dense table, to make sure it is still readable.

The watermark is centred on every page; an image is scaled to fit half the page. To mark only some pages, split them off with Split PDF, watermark that part, and join the file again with Merge PDF. For a small label in the margin instead of a mark across the middle, Header & Footer is the better fit.

Watermark PDF is a hybrid tool. Smaller documents are stamped in your browser. Larger ones use an encrypted upload, are processed automatically with no human access, and are deleted from Siliph's servers within 2 hours. No extra Siliph mark is added; the only watermark is yours.

Free ways to watermark with other software

Word, on Windows or Mac

If you still have the document in Word, add the watermark before you make the PDF. Microsoft's steps: "On the Design tab, select Watermark", then choose a preset "like DRAFT, CONFIDENTIAL, or DO NOT COPY", or use Custom Watermark for your own text or a picture (Microsoft Support). Then save or export the document as a PDF. Microsoft notes one limit: "In Word for the web, you can see watermarks that are already in a document, but you can't change them or insert new ones."

Google Docs, in any browser

Google Docs can add text or image watermarks, which "appear behind your text and will repeat on every page of your document". The command is under Insert, in Page elements, then Watermark. It does not work in pageless documents: Google says the feature "isn't available in documents that are in pageless format" (Google Docs Editors Help). When you are done, choose File > Download > PDF Document.

Mac: Preview

Apple's Preview user guide has no watermark topic. The nearest option is the Text tool in the Markup toolbar, which places a text box you can drag into place (Apple), but you would repeat it page by page and it sits on top as an annotation. For more than a page or two, a watermark tool is faster.

Adobe Acrobat (paid)

In Acrobat on the desktop, open the PDF, select Edit, then "Watermark > Add". You can choose text or a file, adjust "opacity, rotation, and size", set the position, and apply it to multiple files. Adobe notes that "Only PDF, JPEG, and BMP images can be used as watermarks" (Adobe).

iPhone and Android

Open Watermark PDF in Safari or Chrome and choose the file from your phone storage. Typing a short watermark and checking the live preview works well on a phone screen; turn the phone sideways for a larger preview.

Common problems and fixes

Frequently asked questions

How do I add a watermark to a PDF for free?

Open Watermark PDF, upload the file, choose Text watermark or Image watermark, set the opacity and angle, and click Add watermark. Download the result. It is free, needs no account and adds no other mark.

How do I put a logo watermark on a PDF?

Choose Image watermark, upload the PDF first, then add your logo as a PNG or JPG. A transparent PNG looks cleanest. The logo is centred on every page and scaled to fit half the page, and you can set its opacity and rotation.

Can a watermark be removed from a PDF?

Sometimes. A watermark is a visible layer, and someone with a full PDF editor may be able to select and delete it. Treat it as a clear label rather than security, and use a password when you need to control who can open the file.

How transparent should a watermark be?

About half opacity on a diagonal is a good start for words like DRAFT or CONFIDENTIAL. Go lower for dense tables or small print, and lower still for a logo. Check the busiest page before you send the file.

Can I watermark only certain pages?

Watermark PDF marks every page. To mark only some, cut those pages out with Split PDF, watermark that part, then join everything back in order with Merge PDF.