How to add a watermark to a PDF with OnyxPDF
- Drop your PDF into the tool.
- Type the watermark text and set size, colour, rotation and opacity.
- Pick a layout: diagonal centre, centre, tiled, top or bottom strip.
- Choose the pages (blank = all) and click “Apply Watermark”.
Why do it in your browser instead of uploading?
- Full customisation free: layout, angle, opacity and colour are exactly the options competitors lock behind paid tiers.
- Diagonal and tiled modes give real document-protection coverage, not a shy corner stamp.
- No upload: watermark an unreleased draft without it leaving your machine.
- Apply to all pages or a chosen range.
Good to know (honest limits)
- A watermark discourages casual reuse; it is not DRM — a determined person can still work around visible stamps on copied pages.
- Text watermarks only in this tool; for a logo stamp, place the image with Edit PDF.
Frequently asked questions
Can I watermark with my logo image instead of text?
This tool stamps text. For an image stamp, open Edit PDF and place your logo image on the pages.
Can I remove a watermark later?
The watermark is drawn into a new copy of the PDF. Keep your original file if you may need an unstamped version.
Which layout is best for drafts?
Diagonal centre at low opacity is the classic: readable as a warning, light enough to read through. Tiled gives the strongest coverage.
Is my file uploaded?
No. Stamping happens in your browser; the watermarked PDF downloads directly to your device.