What kind of password does this add?

An open password: readers must enter it before viewing the file in standard PDF apps.

Can SnapPDF recover a forgotten password?

No. Store passwords somewhere safe. Unlock only works when you already know the password.

Is my PDF or password uploaded?

No. Protect runs in your browser.

The file is already locked — what should I do?

Unlock it first (if you know the password), then protect again with the new password.

Is password protection enough for highly sensitive data?

It stops casual opening, not every attack. Prefer not emailing highly sensitive files when a secure portal exists.

Free · no signup

Protect PDF

Add a password so the PDF needs it to open. Encryption runs in your browser.

Free PDF tool — runs in your browser

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FAQ

What kind of password does this add?: An open password: readers must enter it before viewing the file in standard PDF apps.
Can SnapPDF recover a forgotten password?: No. Store passwords somewhere safe. Unlock only works when you already know the password.
Is my PDF or password uploaded?: No. Protect runs in your browser.
The file is already locked — what should I do?: Unlock it first (if you know the password), then protect again with the new password.
Is password protection enough for highly sensitive data?: It stops casual opening, not every attack. Prefer not emailing highly sensitive files when a secure portal exists.
Is there a size limit?: 25MB and 100 pages.

How to add a password to a PDF

Password protection stops casual opening of a file you email or upload. SnapPDF adds an open password with AES-256 encryption in your browser. Anyone without the password should not be able to view the contents in standard readers.

Steps

Choose the PDF you want to protect (it must not already be locked).
Enter a password and confirm it — use at least 4 characters.
Download the protected copy and store the password somewhere safe.
Test by opening the download in another app and entering the password.

When to use it

Sending contracts or admin packets by email
Sharing student records or ID scans
Archiving a copy that should not open on a shared computer by default

Tips

If the file is already locked, unlock it first, then protect with the new password.
A strong unique password beats a short reused one.
Password protection is not a substitute for not sending highly sensitive data over insecure channels.

Related tools

Related guides

Password-protect a PDF before you email it
When an open password helps, how to add one in the browser, and what Protect PDF does not replace.
Browser PDF tools and privacy: what stays on your device
A plain-language look at which SnapPDF tools run locally and when a file may be processed briefly on a server.