Open password — controls who can read it
The file is encrypted and asks for the password before showing its contents. This is usually what people mean by password-protecting a PDF.
How to password-protect a PDF on Mac for free
Preview already protects one PDF well. Use a batch tool only when repeating the job becomes the problem.
An open password encrypts the document so it cannot be viewed without the password. Preview can add one without installing anything.
Both methods keep the PDF on your Mac.
Quick answer
Protect one PDF in Preview
Apple's built-in workflow takes about a minute:
- 1. Open a copyOpen the PDF in Preview and keep the original somewhere secure.
- 2. ExportChoose File > Export and give the protected copy a new name.
- 3. Set permissionsClick Permissions and select Require Password To Open Document.
- 4. Enter both passwordsConfirm the open password and enter the required owner password.
- 5. Apply and saveClose the new file, reopen it, and verify that it asks for the password.
These steps follow the Preview User Guide. Apple recommends a new name when you want a protected copy without changing the original.
Choose deliberately
Open password or permissions password?
Permissions password — controls allowed actions
This controls printing, copying, annotations, and changes after the PDF is open. Treat permissions as workflow restrictions, not as a substitute for an open password when the contents themselves are sensitive.
When Preview is enough
Choose the smallest tool that covers the job
Preview — free for one document
Use Preview when you have one or a few PDFs and want an open password or detailed permissions. It is built in and exposes both password types.
PX7 PDF Protect — batches and explicit verification
Use PX7 when you need one open password across a Finder selection or folder, or need password-free copies of PDFs whose current password you know. It checks that a wrong password fails, the chosen password works, and page counts match. €15 once after a seven-day trial.
brew install --cask px7digital/tap/px7-pdf-protectAcrobat Pro — use the licence you already have
Acrobat supports open and permissions passwords and reusable security policies. If your workplace already provides it, use its established workflow.
Before sharing
Do not lose the only usable copy
- Use a unique passwordPrefer a long generated password stored in a password manager.
- Keep the originalPX7 Digital cannot recover a forgotten password.
- Test the copyReopen it with the correct password, then confirm a wrong password is rejected.
- Separate the channelsWhen practical, send the PDF and password by different routes.
Common questions
PDF passwords on Mac
Can I password-protect a PDF for free on Mac?
Yes. Preview can export a PDF copy that requires a password to open, and it can also set a separate owner password for printing, copying, and changes.
What is the difference between an open password and a permissions password?
An open password encrypts the PDF and is required to view it. A permissions password controls actions such as printing or copying after the document is open.
Can a forgotten PDF password be recovered?
Do not assume it can. Keep an unprotected original or another secure copy, and store the password in a password manager.
How should I share a PDF password?
Send the PDF and its password through separate channels when practical, and avoid putting both in the same email or message.