Banks, landlords, employers, mobile networks and schools regularly ask for copies of your CNIC, passport, utility bills or degrees. Once that copy leaves your hands, you don’t control where it goes. A watermark is a simple, free way to limit what someone can do with it.

Why watermark an ID copy?

Copies of identity documents are used for fraud, such as opening accounts, registering SIM cards or applying for loans in someone else’s name. A copy that clearly says “For ABC Bank account opening only, 01/11/2026” is much harder to reuse, because anyone checking it can see it was given for a different purpose and on a different date.

A watermark doesn’t stop the organization you sent it to from doing its job. They can still read every detail they need to check.

What to write

A good ID watermark answers three questions: who it’s for, what it’s for, and when. For example:

  • For ABC Bank account opening only, 01/11/2026
  • Copy for XYZ Properties rental, Nov 2026
  • For job application at DEF Ltd only

Keep it short enough to fit across the page at a readable size.

Step by step

  1. If your ID copy is a photo, first turn it into a PDF with JPG to PDF. For the front and back of a card, add both photos to make a two-page PDF.
  2. Open Add Watermark and add the PDF.
  3. Type your watermark text.
  4. Set the font size. For a sentence like the examples above, 24 to 36 points usually fits across the page. Short words like COPY can be much larger.
  5. Set the opacity around 20 to 30%. The text should be clearly visible but leave the ID details readable.
  6. Keep the angle diagonal, so the text crosses the important parts of the document.
  7. Click Add watermark and check the result before sending.

Make sure the details stay readable

The receiver still needs to read your name, number and photo. If the watermark covers the photo or number so heavily that they’re hard to read, lower the opacity or use a lighter color such as grey or blue. A document that can’t be checked may be rejected.

Extra steps for sensitive documents

  • Send only what’s needed. If someone needs page 1 of a document, don’t send all five pages. Use Extract Pages.
  • Password protect it before emailing, and send the password separately. See how to password protect a PDF.
  • Don’t use upload-based tools for ID documents. Uploading your CNIC to an unknown converter defeats the purpose. Convertpdfly adds watermarks in your browser, so your ID never leaves your device.
  • Keep a clean original in a safe place, and make a new watermarked copy for each request.

How strong is a watermark?

A determined person with editing software could try to remove a watermark, especially a light one. It’s a deterrent, not a lock. Its real strength is that it makes casual misuse obvious, and that’s usually enough to make a stolen copy useless.

Watermark text currently supports English letters, numbers and common punctuation. Read more about privacy in our article Are online PDF tools safe?