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Jun 4, 2026 · 1 min read

How to Mark a PDF as Confidential with a Watermark

Add a CONFIDENTIAL stamp to protect documents.

CT
ChangeMyPDF Team
ChangeMyPDF

A visible CONFIDENTIAL watermark discourages unauthorized sharing and labels drafts clearly.

ChangeMyPDF runs entirely in your browser — your files never leave your device, there's nothing to install, and you can start without an account. Here's exactly how to do it.

Step-by-step

  1. Open the Watermark tool and add the PDF.
  2. Type CONFIDENTIAL as the watermark.
  3. Set a diagonal angle and medium opacity.
  4. Download the watermarked file.

Tips for the best result

  • Diagonal text is hard to crop out.
  • Keep opacity low enough to read the content.

Is it safe and free?

Yes. Most ChangeMyPDF tools process files locally in your browser, so documents are never uploaded to a server. Free accounts can run a few operations per hour; a Week Pass or Premium plan removes the limit and ads if you need to do more.

Frequently asked questions

Do my files get uploaded to a server?

For most tools, no — the work happens in your browser, so your documents stay on your device.

Is it really free?

Yes. Free users get a few runs per hour. For unlimited use and no ads, grab a $5 Week Pass or a Premium plan.

Which browsers are supported?

Any modern browser — Chrome, Edge, Firefox, and Safari on desktop and mobile.