🔒 PDF300
Put a password on a PDF
The file has to be emailed but not to just anyone who ends up with the message. A password means the wrong hands get a locked file.
Open the toolRuns on our server — the file is uploaded, processed and sent back.
How it works
- Add the PDFThe file is sent to the server to be locked.
- Set the passwordSend it to the reader some other way — not in the same email as the file.
- DownloadSave the locked file.
Questions
Yes — this one runs on a server, so the file is sent over the network and processed there. If you would rather nothing left your device, use the browser tools on the main page instead.
Neither. No account, no watermark on the output. The practical limit is your device memory — large scanned files use more of it.
Guide: protecting a PDF well
When you'd use this
A document going by email is readable by anyone who ends up with a copy of that email, forwarded or misdirected or sitting in an inbox someone else has access to. A password turns a file that anyone can open into one that only someone with the password can open — useful for payslips, tax documents, contracts in progress, or anything that should not be readable just because a message landed in the wrong mailbox.
How it works
The file is uploaded, encrypted on the server with the password you set, and sent back as a new file; your original is untouched. The server does not keep a copy of the file or the password once the response is sent back to you.
Sending it safely
A password is only useful if it does not travel with the file. Sending both in the same email defeats the purpose, since anyone who intercepts or forwards that message has everything they need. Send the password a different way — a text message, a phone call, a separate email thread, or a password the recipient already knows (a shared reference number, for example) — so that having the file alone is not enough.
What kind of protection this is
This sets PDF standard encryption with an open password, meaning a PDF reader will refuse to display the file's contents at all without the correct password — this is different from a "permissions password" that merely restricts printing or editing while still letting anyone view the file. If you later need to remove the lock — because you are the recipient and the password has been shared properly, or you decided the file no longer needs it — use Remove PDF password, which needs the same password to unlock it.
More questions
There is no recovery — the server does not keep a copy. Keep the password somewhere safe before you close the tab, such as a password manager.
This tool sets a single open password. More granular permission controls (view but not print, for example) are a separate PDF feature not covered here.
Remove the existing password first with Remove PDF password, then set a new one — the tool does not re-encrypt an already-locked file directly.
The upload travels over HTTPS like the rest of the site; the file is processed in a temporary location on the server and is not kept after the response is returned.