How to Password-Protect a PDF
Sharing a PDF with sensitive information over email often calls for a password. Protect PDF encrypts your document so it can’t be opened without the password you choose — and because encryption happens locally, that password never leaves your device either.
Steps
- Open Protect PDF and upload your document.
- Enter a password and confirm it. PageFlow shows a strength indicator as you type.
- Export. The result is a new, encrypted copy — your original, unprotected file is untouched.
PageFlow never stores your password
This is worth being explicit about: the password you set is used only in memory, at the moment of encryption, to build the protected file. It is never transmitted anywhere, never logged, and never written to browser storage. That also means PageFlow cannot recover a forgotten password — there’s no “reset” option, because there’s no server-side record of it to reset. Write it down somewhere safe before you close the tab.
Choosing a good password
A longer, unique password is more effective than a short, memorable one. Since you control both ends of this (you’re setting the password and, presumably, sharing it separately with whoever needs to open the file), consider a passphrase of several unrelated words rather than a single short word with substitutions.
What password protection does and doesn’t do
Setting a password restricts opening the document. It is a real, useful protection for casual sharing — but it is not equivalent to enterprise-grade document rights management, and reader compatibility for the strongest encryption settings can vary slightly between different PDF viewers. If you need to grant different permissions to different people (view-only vs. edit, for example), that’s a different problem than a single open-password.
Sharing the password separately
Never send the PDF and its password in the same email or message — if that thread is compromised, the password protection is moot. A separate channel (a text message, a phone call, a password manager’s sharing feature) keeps the two apart.
If you need to remove protection later
Once you or your recipient has the correct password, Unlock PDF reverses this — see How to unlock a PDF when you know the password for that process.