Add Watermark to PDF Online Free - PDF Watermark

How to add a watermark to a PDF online - free

A watermark is semi-transparent text overlaid on document content to indicate its status, authorship or usage restrictions. Terms like "CONFIDENTIAL", "DRAFT", "UNCONTROLLED COPY" or the company name are the most common in corporate environments. This tool lets you add any text as a watermark to all pages of a PDF in seconds, directly in the browser.

You can customize the text, opacity (from nearly invisible to clearly visible), size (small, medium or large), color and rotation angle. The diagonal angle (45°) is most commonly used as it makes simple removal by cropping the text harder, but horizontal and vertical angles are also available for specific cases. The preview shows how it will look before processing the file.

Processing uses the pdf-lib library directly in the browser. The text is rendered on each page using standard PDF fonts (Helvetica), ensuring compatibility with any reader. No data is sent to servers - the original file and the result stay only on your device.

Important: the watermark added by this tool is embedded in the page content, but it is not a security protection. Users with advanced tools may attempt to remove it. For more robust protection, combine with the Protect PDF with Password tool.