Aadhaar copies, salary slips, bank statements, mark sheets: we send these as PDFs all the time, over email and WhatsApp, where they sit in chats and inboxes for years. Adding a password means only the person you give it to can open the file.

How to add a password in 3 steps

Our free Protect PDF with Password tool locks the file in your browser, so neither the PDF nor the password goes to any server.

  1. Add your PDF. Drop it in or tap to choose it.
  2. Type a password twice. The second box catches typos, which matter here because there's no way to reset it.
  3. Download the locked PDF. It now asks for the password every time it opens, in any PDF reader.

Under More options you can also stop people copying text out of the PDF.

Choosing a good password

Bank statements are often locked with a date of birth or part of a PAN, because the bank needs something you already know. That's easy to guess for anyone who knows you, too. For files you lock yourself:

  • Use at least 8 characters, with letters and numbers. The tool tells you when a password is easy to guess.
  • Don't send it with the file. If the PDF goes by email, send the password by SMS or a call.
  • Avoid your phone number or birthday for anything sensitive.

How strong is the lock?

The tool uses AES-256, the strongest encryption the PDF format supports. It works in Chrome, Edge, Adobe Reader, and the PDF viewers on Android and iPhone. Your pages, text and links stay exactly the same, because the file isn't redrawn.

What if I forget the password?

It can't be recovered. AES-256 isn't something any website or app can "crack", and that's the point of it. So:

  • Keep the original, unlocked file somewhere safe on your own device.
  • Note the password in a password manager or a notebook you trust.

Removing the password later

If you know the password, you can remove it with our PDF Password Remover. That's handy when a portal won't accept a locked file.

Frequently asked questions

Does locking a PDF make it bigger? Barely. It adds a few hundred bytes. If you need it under a KB limit, compress it first with Compress PDF, then lock it.

Can I lock a PDF on my phone? Yes. Open the tool in your phone's browser, choose the PDF from your files, and download the locked copy. No app is needed.

Will the person need special software? No. Any normal PDF reader asks for the password and opens the file.

Ready to lock a file? Open Protect PDF with Password and it's done in seconds.