Drop a PDF to add watermark
Stamp text diagonally across every page
Or drag and drop them here
Your files stay on your device · 0 uploads
PRIVATE PDF TOOL
Add Watermark to PDF
Stamp custom text across PDF pages. Set opacity, angle, and position — all in your browser.
100% client-sideNo server involved
No uploadsYour files stay private
No account neededStart merging instantly
How it works
Merge your PDFs in just a few clicks.
1. Upload your PDF
Select the PDF you want to watermark.
2. Design your watermark
Enter text and adjust font, size, color, and opacity.
3. Set position
Choose diagonal, center, or corner placement.
4. Apply and download
Download the watermarked PDF — no upload needed.
Your files never leave your device.
WhisperDocs runs entirely in your browser. All processing happens locally on your device, with no uploads, no accounts, and no tracking. Ever.
Processed in your browser
100% private
You stay in control
Common questions
Everything you need to know about merging PDF files with Watermark PDF.
Yes. Enter any text — such as "Confidential" or your company name — and customize font size, color, opacity, and position.
Yes. Watermarks are applied to every page in the PDF by default, or you can target specific pages.
Yes — the watermark is embedded into the PDF. It cannot be removed without specialized software.
No. Watermarking runs entirely in your browser. Your document never leaves your device.