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Watermark PDF online

Choose a PDF, add your text, and download a watermarked copy. English and Thai text supported.

1. Choose & customizeWatermark text

PositionOpacity — 25%Text size — 10%ColorPages (leave blank for all)

2. Preview

Your PDF preview will appear here.

Start at 20–30% opacity so the document remains readable. Long text automatically shrinks to fit.
For a document copy, include its purpose, recipient, and date. Preview every important page before downloading.
A watermark is a visible label, not password protection or redaction. It does not prevent copying or removal.
The original pages stay as PDF content; only the watermark is an image. Editing invalidates digital signatures. Keep the original and check forms and links in the result.