How to Add a Password to a PDF on Mac (Free, Built-In Method)

Two Free Ways to Password Protect a PDF on Mac

Mac users have two good options for adding a password to a PDF: the built-in Preview app and a free online tool.

Method 1: Preview (Built into macOS)

Preview is macOS's built-in PDF viewer and it can add password protection for free:

1. Open your PDF in Preview

2. Go to File → Export as PDF

3. Click the Permissions button (bottom left of the export dialog)

4. Check Require password to open document

5. Enter your password and confirm it

6. Click Apply then Save

Your PDF is now password-protected. Anyone who tries to open it will be prompted for the password.

Note: Preview uses 128-bit RC4 encryption, which is older than the AES encryption used by newer tools. For sensitive documents, a more modern encryption method is recommended.

Method 2: Breklo Online Tool (Stronger Encryption)

For better security (128-bit AES), use Breklo's Password Protect PDF tool:

1. Go to breklo.com/password-protect-pdf

2. Upload your PDF

3. Enter a password (minimum 4 characters)

4. Confirm the password

5. Click Protect PDF

6. Download the protected PDF

All processing happens in your browser — the file never leaves your Mac.

Choosing a Strong Password

A strong PDF password should be:

• At least 8 characters
• A mix of letters, numbers and symbols
• Not based on a word or name
• Unique — not used for other accounts

Removing a PDF Password on Mac

To remove a password you added:

1. Open the PDF in Preview (enter the password when prompted)

2. Go to File → Export as PDF

3. Click Permissions

4. Uncheck Require password to open document

5. Save

What Preview Password Protection Does and Does Not Do

Preview's password protection prevents opening the document without the password. It does not prevent screenshots, printing or other actions once opened. For stricter document control, use a tool that supports permission restrictions.

Try these free tools

Frequently asked questions