Watermark your ID copy before you share it for KYC

The short answer: write the purpose across the copy

KYC means "Know Your Customer": the ID check that banks, SIM sellers, landlords, hotels, gyms and many others ask for. They want a copy of your Aadhaar, PAN card or passport, and that copy may sit in a phone or a drawer for years. Writing what it is for across the copy, with the date, makes it awkward to reuse for anything else. Here is the quick way:

1. Make the copy a PDF. A photo goes through JPG to PDF first. A scan that is already a PDF is ready. A PDF you downloaded may need unlocking first (see getting the copy ready).
2. Open Add Watermark and press Choose PDF files. Pick the PDF.
3. Type the words under Text: what it is for, who it is for, and the date. For example: For SIM card KYC only, 8 Oct 2026.
4. Choose Repeated, a size of about 24 points (points measure the size of letters), and an opacity of 30% to 40%. Opacity is how solid the words are: lower lets the card show through.
5. Check the cards. You must still be able to read every number and name through the words.
6. Press Add watermark, then Download. Send the new file, which is named like aadhaar-watermarked.pdf, and not the original.

The stamping happens on your own phone or computer. Your ID copy is never uploaded. That matters more here than for almost any other file.

What a watermark does for an ID copy, and what it doesn't

Be clear about this first, so you don't feel safer than you are. The words go on top of the card. At a low opacity they don't hide it, and they are not meant to. The number, your name and your photo stay readable on purpose, because the person checking them has to read them.

So treat it as one good habit among several. The others follow below: share less, share carefully, and keep a record.

Get the copy ready first

Send only what is needed

Ask what exactly they need: which document, which side, and whether a masked copy will do. When you download e-Aadhaar from UIDAI, you can choose a masked copy, which hides most of the number and shows only the last four digits. If the other side accepts it, a masked copy is the safest one, because the hidden digits are not there to be misused. A watermark can't hide digits, so only a masked copy can do that.

Add Watermark has an Only some option, but it stamps the pages you choose and leaves the other pages in the file, unmarked. To leave out a page, such as the back of a card, remove it first with Organize PDF or keep only the page you want with Split PDF.

If you have a photo

The tool stamps PDFs. Photos go through JPG to PDF first, one picture per page, in the order you set. If a card has a front and a back, put both in one PDF only if both are needed. Photos carry hidden notes you can't see, such as the camera and often the exact place where the picture was taken. JPG to PDF leaves those notes out of the PDF and tells you when it did. A clear, straight, well-lit photo is easy to read through a watermark, so lay the card flat and avoid glare.

If you downloaded a PDF

Documents downloaded from government sites, like an e-Aadhaar PDF, often arrive locked with a password. Add Watermark can't use a locked file. Its card says "Locked with a password". Remove the password first with Unlock PDF, which needs the password you already have. If you don't know how the password is made, the website you downloaded it from explains it. We don't list any site's rule here, because rules change. Then stamp the unlocked copy.

If the PDF is digitally signed

Some official PDFs carry a digital signature, a coded seal that shows they haven't changed. A stamped copy is a changed copy, so it no longer carries a valid signature, and the result says so. If the receiver says they will check that signature, send the original the way they ask, and don't mark it.

What to write across it

Use three parts: what it is for, who it is for, and the date. Short is better, because the words repeat across the whole page. Some examples:

• Add the receiver's name if you can. "Given to Mr Rao, the owner" is clearer than "given to the owner". If the copy ever shows up somewhere it shouldn't, the name tells you which copy it was. Anyone can cut out a visible name, so treat this as a clue, not proof.
• Keep the date clear. Write the month in letters, like 8 Oct 2026, so nobody mixes up day and month.
• Don't put private numbers in the words. Your Aadhaar number or phone number inside the mark would only repeat them across the page.
• Write in English letters. The typed words use a standard font with Latin letters, digits and common punctuation, but not Devanagari or other scripts. You can write Hindi in English letters, like "Sirf SIM KYC ke liye, 8 Oct 2026". The rupee sign isn't drawn either, so write Rs.
• One line, up to 200 characters. If you type something the font can't draw, the box says which character, and nothing is saved until you fix it.

Settings that keep the copy readable

The words must be strong enough to matter and light enough to read through. These choices work for cards and certificates:

Then check. The cards are small, so after saving, open the new PDF and zoom in on one page. You can use PDF Viewer right in the browser. Look at these:

• The numbers. Can you read every digit? If you struggle, so will the person checking. Lower the opacity or the size.
• The name and date of birth. The words can cross them, but each letter must still be clear.
• The photo. A face with faint words across it is fine. A face you can't recognise is not.
• The QR code. Aadhaar copies carry a QR code. Words across it may stop it from scanning. If the receiver may scan it, test it from the screen, or ask if they need it.

If you are marking several papers for the same purpose, such as Aadhaar, PAN and a bank statement for one loan, add them together. All of them get the same words, and you download them in one ZIP file named watermarked-pdfs.zip. The guide's part on marking ID copies has the same recipe in short. For other jobs, like DRAFT on a report or a logo on a price list, see how to add a watermark to a PDF.

A worked example: a flat on rent

Say Priya is renting a flat in Pune. The owner asks her for her Aadhaar and PAN on WhatsApp. Here is what she does:

1. She has a photo of each card. She puts both into JPG to PDF, with Aadhaar first. She gets one PDF with two pages.
2. In Add Watermark she types For flat rental only, given to Mr Rao, 8 Oct 2026. She chooses Repeated, 24 points, an opacity of 35% and Diagonal.
3. She reads the cards, saves the PDF, opens it and zooms in. Every digit is readable through the faint grey words.
4. She sends the marked PDF, not the photos. In her phone she notes "Rao, flat, 8 Oct".
5. When the agreement is signed, she deletes the PDF from Downloads and from the chat.

Nothing here stops a determined person. But if Priya's Aadhaar later turns up on a loan form, the words "For flat rental only, given to Mr Rao" are right there on it, and she knows which copy it was.

Making the mark harder to remove (optional)

A watermark made by this tool is a separate layer on top of the page. That is why PDF editing software can select it and delete it. If you want it fixed into the page, turn the pages into pictures and the pictures back into a PDF:

1. Stamp the PDF as above and download it.
2. Open PDF to JPG and add the stamped PDF. Normal sharpness suits most uses. Choose High if the small print on the card matters. Each page becomes a picture that shows the page as it looks, with the watermark in it. The page is drawn again, so a scan is not pixel for pixel the same. A one-page PDF gives one picture with its own Download button. Several pages give a Download all (ZIP) button, and each picture also has its own Download button, so on a phone you can save them one by one.
3. Open JPG to PDF and add the pictures in page order. Each JPG goes into the PDF exactly as it is, without losing quality.
4. Use the new PDF. Check the numbers again.

Now the watermark is part of the picture. A PDF editor sees one flat picture per page, with nothing separate to select and delete. Someone would have to edit the picture itself, and that is slower and harder, particularly when words cross the digits and the photo. But it is not impossible, and we can't promise it stops anyone.

There are two costs. The words on the page can no longer be searched or copied, which makes no difference for a scan that was only a picture. And the file may be bigger than the stamped PDF. If it is too big for a form or email, shrink it with our PDF compressor.

Sending the marked copy safely

• Send the marked copy, never the original scan. Keep the original in a private folder. Add Watermark never changes it.
• Use the service's own upload page or office where there is one, instead of a forwarded chat. Chats get forwarded and backed up.
• Lock it if you send it to a person. Protect PDF adds a password. Tell the password by phone or in person, not in the same chat. Many upload portals can't read locked PDFs, so for those, skip the password.
• Name the file plainly. Don't put your ID number in the file name.
• Keep a small note of who got which copy and when. It takes a minute and helps if a copy surfaces somewhere.
• Delete copies when the job is done: the one in Downloads, and the one in the chat, if you can. Ask the receiver how long they keep it.

If you think a copy is being misused, act quickly. Contact the body that issued the document (UIDAI for Aadhaar, the Income Tax Department for PAN), tell your bank if an account or money is involved, and report it to the cyber-crime police. This article is everyday good practice and not legal advice.

When a marked copy is not the right answer

• The receiver needs a clean copy. Some banks and offices may not accept a copy with words across it. If the form is official and the rule is strict, don't argue. Use their own upload page, or take the document to the branch.
• A checked signature is needed. A stamped copy no longer carries a valid digital signature, so send the original when it will be checked that way.
• The copy is already out there. A watermark helps with copies you are yet to share. It can't mark copies you sent before.
• A stranger asks. A marked copy is still a copy. A caller who says they are from a bank, a courier or the government and wants your documents or an OTP is a reason to stop, not to mark.
• You need strong protection. A watermark is a label. For real protection, share a masked copy where you can, lock files with a password, and use the right channel.

Questions people ask next

Can I mark a photo of my card directly?

No. Add Watermark stamps PDFs, and a picture dropped on its page becomes the watermark. Turn the photo into a PDF with JPG to PDF first.

Will the other side accept a marked copy?

That depends on who asks. Light words with every detail readable give you the best chance. For an official process, ask first.

Can I use different words for each receiver?

Yes. Always start from your original, not from a copy you already marked. Stamping a marked copy again would add a second set of words on top of the first.

Can I put the words in Hindi?

Not as typed words. Write them in English letters, or make a picture of the Hindi words and use it as a picture watermark.

Is it safe to use an online tool for an ID?

It depends on the tool. Many online PDF tools upload your file to their servers. This one keeps the file on your device. On a computer you can check in the browser's network panel (part of its developer tools) that nothing is uploaded.

Does it work on a phone?

Yes, in Chrome on Android or Safari on iPhone and iPad. The new PDF goes to Downloads.