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Add watermark to PDF

Stamp text like “CONFIDENTIAL” or your logo on every page – free, private and right in your browser.

or drop a file here

Processed on your device – files are never uploaded

A watermark tells readers at a glance that a document is a draft, confidential, a copy or yours. With PDF4U you type the text or pick a logo, choose how it looks and where it goes, and see a live preview before you create the file.

The watermark is added by your own browser, so contracts, ID scans and internal reports never leave your device. Text is written as real, selectable PDF text in any script – Latin, Thai, Hindi, Arabic, Japanese and more – with a matching font embedded only for the letters used. Put it over the page, or under the content so the text stays perfectly readable, at any angle you like.

For most documents, a light grey or colour at 20–40% opacity, rotated 45°, is easy to see without hiding the text underneath. For photos or designs you share online, a repeated (mosaic) watermark makes it much harder to crop out.

How to add a watermark to a PDF

  1. Select your PDF

    Click “Select PDF file” or drop a PDF onto the page. A preview of the first page appears.

  2. Design the watermark

    Type your text or choose an image, then set the size, colour, opacity, angle (any value from −180° to 180°), position and layer – over or under the content. Tick “Repeat across the page” for a mosaic.

  3. Choose the pages

    Keep “All pages” or enter only the pages you want, for example 1-3, 5.

  4. Add it and download

    Click “Add watermark”, then “Download”. Want to make it harder to remove? Continue with Protect PDF.

Frequently asked questions

Is my PDF uploaded when I add a watermark?

No. PDF4U adds the watermark inside your browser on your own device. Your file is never sent to a server.

Can I use my logo as a watermark?

Yes. Choose “Image” and select a PNG or JPG. A PNG with a transparent background looks best. You can set its width, opacity, angle and position.

Does it work with Thai, Hindi, Vietnamese or other languages?

Yes. Text in Thai, Hindi, Bengali, Arabic, Urdu, Japanese, Chinese, Vietnamese and other scripts is written as real PDF text with an embedded Noto font, so it stays sharp and can be searched and copied. Only scripts without an output font, such as Korean or emoji, are added as a high-resolution image.

Can I watermark only some pages?

Yes. Choose “Only these pages” and enter page numbers or ranges such as 1-3, 5, 8-.

Can the watermark go behind the text?

Yes. Choose “Under the content”: the watermark is painted first and the page’s text and pictures on top, so everything stays readable. On scanned pages, which are one big picture, it would be hidden – keep “Over the content” there. A determined person with a PDF editor can remove any watermark; to make that harder, add a password with Protect PDF.

Is it free?

Yes. Adding watermarks is free, with no sign-up and no limits on file size or number of pages.

How do I make the watermark transparent?

Lower the opacity slider. Around 20–30% keeps the page readable while the watermark stays clearly visible; 100% is fully solid.