How to Password Protect a PDF

Quick answer: Add a password to a PDF so it cannot be opened without credentials. Open PDF 加密 — everything runs locally in your browser, and files never leave your device.

Steps

1. Upload the PDF to the Protect tool.
2. Enter a strong password (a passphrase of 12+ characters beats short random strings).
3. Confirm the password and download the encrypted PDF.
4. Share the password through a different channel than the file itself.

Important notes

• This is standard PDF encryption — supported by Adobe Reader, browsers, and mobile viewers.
• If you lose the password, the file cannot be recovered; there is no master key.
• Encrypting does not stop screenshots, so treat it as access control, not anti-leaking.

Common questions

Can I remove the password later? Yes — open the file with the password, then use the Remove Password tool to save an unprotected copy.

Do recipients need special software? No, any modern PDF viewer will prompt for the password.