Add Watermark to PDF
Free online PDF watermark tool: stamp custom text (e.g. CONFIDENTIAL) across every page. Runs 100% in your browser — no upload.
About Watermark PDF
Mark a document as CONFIDENTIAL, DRAFT, or anything else: this tool stamps your text diagonally across every page of the PDF, semi-transparent so the content stays readable. Everything runs locally in your browser.
How to use Watermark PDF
- Drop a PDF file into the upload area.
- Type the watermark text.
- Click Process and download the watermarked PDF.
Frequently asked questions
Is Watermark PDF really free?
Yes — Watermark PDF is completely free, with no account, no watermark, and no usage limits. It runs entirely in your browser.
Are my files uploaded to a server?
No. All processing happens locally on your device using WebAssembly. Your files never leave your computer — close the tab and nothing remains.
Which browsers are supported?
Any modern browser on desktop or mobile: Chrome, Firefox, Safari, and Edge.
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