How to Password Protect a PDF Online for Free
Lock any PDF with a password so only people you choose can open it. Runs entirely in your browser — nothing is ever uploaded.
When a password-protected PDF makes sense
Sending a confidential file through email or a shared drive means the file can be opened by anyone who receives it. Adding a password restricts who can actually view the contents.
It's the standard for sharing quotes, bank statements, tax documents, employment offers and NDAs — anytime the recipient is known but the channel is not private.
Locking a PDF without uploading it
The Protect PDF tool encrypts your file locally in the browser. You pick a password, and the tool re-writes the PDF with encryption applied and all existing features still intact for the right people.
Nothing is uploaded, which matters here especially: the point of protecting a file is keeping it out of the wrong hands, and a lock should never require sending the unlocked original to a server first.
Choosing a strong password
Use a phrase or a password from a generator rather than a word. The lock is only as strong as the password, and modern tools can brute-force short passwords in seconds.
Share the password on a separate channel from the file — an email with the PDF and a different message with the password — so intercepting one doesn't unlock the other.
Try it free — Protect PDF
Encrypt any PDF with a user password so it needs one to open — generated locally, nothing is uploaded.
Open Protect PDF