How to watermark NID and certificate copies before sharing

The simplest way to watermark NID copy files is to write who the copy is for, why you are giving it and the date right across it, for example "For XYZ Bank account opening only, 5 Nov 2026". Our free Add Watermark to PDF tool does this in your browser: you open the PDF of your NID or certificate, type that line, place it across the page at low opacity and download the marked copy. Nothing is uploaded.

This guide covers what to write, how to turn a photo of your card into a PDF, the exact settings to use and what a watermark can and cannot do.

Why mark your NID copy at all

In Bangladesh a copy of the national ID card goes almost everywhere: bank accounts, SIM cards, job applications, house rent, school admission, mobile wallets. Each copy sits in someone else's file, inbox or WhatsApp chat for years.

Those copies can be misused. Bangladeshi newspapers have reported SIM cards being registered with copies of other people's NIDs, and in 2023 the Election Commission confirmed that citizens' NID details had leaked through some of the organisations connected to its server. You cannot control what happens to a copy after you hand it over, but you can make it less useful to anyone who wants to reuse it.

A line like "For XYZ Bank account opening only, 5 Nov 2026" helps in three ways:

• It shows the purpose. A copy marked for a bank looks wrong when it turns up on a SIM form or a loan application.
• It shows the date. An old copy is easy to spot.
• It spoils the clean image. Someone who wants a clean copy of your card has to remove the text first.

Be realistic, though. A watermark is a deterrent, not a legal shield. It does not make misuse a separate offence and it cannot stop a determined person with editing software.

What to write on the copy

Keep it to one line. The tool takes up to 200 characters and puts the text on a single line, so short is better.

Part	Example	Why
Who it is for	XYZ Bank, ABC Ltd HR	Ties the copy to one receiver
Purpose	account opening, job application	Rules out other uses
Date	5 Nov 2026	Shows when it was given
Limit (optional)	only, not valid for other use	Makes the intent plain

Good examples:

• For XYZ Bank account opening only, 5 Nov 2026
• ABC Ltd job application only, 5 Nov 2026
• House rent agreement, Flat 4B, 5 Nov 2026

You can write the line in Bangla too. Text that the standard PDF fonts cannot show is drawn as a picture using your device's fonts, so check the preview to make sure it looks right.

Step 1: turn your NID or certificate into a PDF

The watermark tool works on PDFs, so start there.

• Paper card or certificate: open Image Studio, tap Scan with camera and choose ID card. Scan the front, then the back. When you tap Done, both sides are placed on one A4 page at real card size, ready to save as PDF. Our guide on scanning documents with your phone has tips for a clean shot.
• Photos you already have: use JPG to PDF to turn them into one PDF.
• A PDF already: go straight to the next step.

How to watermark NID copy, step by step

1. Open Add Watermark to PDF and choose your PDF. If it has a password, type it when asked.
2. Leave the type on Text and replace the sample text with your line.
3. Set the font size to about 20–28 pt. A long sentence at the default 60 pt runs off the page.
4. Pick a dark colour such as dark grey, navy or red.
5. Set opacity to about 25–35% so the card's details still show through.
6. Choose Tiled (repeat across page) as the position. The line then repeats over the whole page, including both sides of the card, so it cannot be cropped away.
7. Keep rotation at 30–45° so the text crosses the photo and the number.
8. Leave Pages on All pages, check the live preview, then click Add watermark & download.

The marked copy is saved with "-watermarked" added to the file name. Your original file stays as it was, so you can make a fresh copy with a new purpose next time.

Settings at a glance

Setting	NID copy	Certificate
Font size	20–28 pt	24–36 pt
Opacity	25–35%	15–25%
Rotation	30–45°	30–45°
Position	Tiled	Tiled or Centre

Certificates have more small print, so a lighter, slightly larger watermark keeps them readable.

Make the watermark harder to remove

The watermark is drawn on top of the scan. Someone with PDF editing software could delete that layer and get your clean card back. To bake it into the picture:

1. Open the watermarked PDF in PDF Studio, switch to Advanced (More tools) and use Convert → PDF → JPG.
2. Put the images back into a PDF with JPG to PDF.

Now the text is part of the image itself. If the file gets too big for an online form, see how to compress a PDF to 1 MB.

A watermark is not security

A watermark tells people what a copy is for. It does not stop anyone from opening or reading it. For real protection:

• Add a password with Protect PDF before emailing the file, and send the password by a different route, such as a phone call or SMS. If your original PDF had a password, the watermarked copy does not, so add one again.
• Remove what is not needed. If the receiver does not need your date of birth or address, black it out with Redact in PDF Studio. Redacted text is removed from the file, not just covered. Many offices do need the full NID number, so ask before you hide it.
• Share on purpose. Do not post your NID in groups or public pages, and delete old copies from chats when you can.

Worried that your NID is already being misused for SIMs? You can dial *16001# and enter the last four digits of your NID to see how many SIMs are registered to it.

Quick checklist

• One clear line: who it is for, the purpose and the date
• NID front and back on one PDF page (Image Studio ID card mode)
• Font size 20–28 pt, opacity 25–35%, Tiled, 30–45°
• Photo, name and number still readable in the preview
• Optional: flatten to an image so the mark cannot be lifted off
• Password added before emailing; unneeded details redacted
• A fresh copy for each new purpose