How to Password Protect a PDF for Free
Bank statements, salary slips, ID copies and contracts often travel by email or WhatsApp. Adding a password means that if the file ends up in the wrong hands, it cannot be opened without the password. It takes less than a minute.
Step by step
- Open Protect PDF on your phone or computer.
- Choose the PDF you want to lock.
- Type a password, then type it again in the second box.
- Choose the protection:
- Password needed to open: anyone with the password can open, print and copy.
- Password to open + block copying and editing: people can still open and print, but normal PDF readers stop them copying text or changing pages.
- Press Protect PDF and download the new file. Open it once to check the password works.
How to choose a good password
- Use at least 10 characters, mixing words and numbers, for example
Blue-Camel-2026. - Do not use your name, phone number or date of birth.
- Use a different password for each important document.
Share the password the safe way
Never send the password in the same email or chat as the file. Send the file by email and the password by phone call or SMS, or agree on it in person. That way one stolen message is not enough to open your document.
How strong is it?
Protect PDF uses AES-256 encryption, the strongest standard available for PDF files. The weak point is almost always the password itself, so choose a long one.
Forgot the password?
Your password never leaves your device, so nobody, including us, can recover it. Always keep an unlocked copy of important files somewhere safe. If you know the password and want to remove it later, use Unlock PDF.
Frequently asked questions
Is it free to add a password to a PDF?
Yes. Protect PDF is free, needs no account and adds no watermark.
Is my file uploaded?
No. The encryption happens in your browser, so your file and your password stay on your device.
Will the PDF open on other phones and computers?
Yes. Any normal PDF reader, such as Adobe Reader, Chrome, Edge or the iPhone Files app, will ask for the password and then open it.
Can I remove the password later?
Yes. Use Unlock PDF and type the password.
Can I protect a PDF that is already locked?
Unlock it first with its current password, then protect it again with a new one.