Protect PDF

Protect PDF online for free. Add a password to encrypt your pdf in seconds — fast, secure, and with no software to install.

📄
Drop your PDF file here
or click to choose — files stay private and are deleted automatically
The password needed to open the protected PDF.

How to add a password to encrypt your PDF

  1. Step 1Upload your PDF file. Drag and drop it into the box above, or click to browse your device.
  2. Step 2PDF4 will add a password to encrypt your PDF automatically — processing runs in seconds, no settings to fiddle with.
  3. Step 3Download your password-protected PDF. Files are sent over a secure connection and deleted automatically within a few hours.

Frequently asked questions

Is the Protect PDF tool free to use?

Yes. You can add a password to encrypt your PDF right here online for free — no account, email, or credit card required. Sign up only if you want higher limits, larger files, or API access.

Are my files safe and private?

Yes. Uploads travel over an encrypted HTTPS connection, are processed on our servers, and are automatically deleted within a few hours. We never share or sell your documents.

Do I need to install any software?

No. PDF4 works entirely in your web browser, so there is nothing to download or install. It runs on Windows, macOS, Linux, Android, and iOS.

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