How to Password Protect a PDF on Mac (Free)

How do I password protect a PDF on Mac with Preview?

To password protect a PDF on Mac, export it from Preview with a password set under Permissions. It takes about a minute, and you can keep the original as it was.

These steps follow Apple's Preview User Guide:

1. Open the PDF in Preview.
2. Choose File → Export. To keep an unprotected original, type a new name, like "contract-protected".
3. Click Permissions.
4. Select Require Password To Open Document, then type the password and retype it to verify.
5. In the Owner Password section, type a password and retype it. It can be the same as the open password or different.
6. Click Apply, then click Save.

Apple notes that the changes take effect the next time the PDF is opened. So close the file, open the new copy, and check that it asks for the password. That's it. You've locked your first PDF.

What the checkboxes do

Under Permissions, each checkbox is an action, like printing or copying text. Apple's guide says a selected box lets people do that without the owner password. Leave a box unselected and that action needs the owner password.

Can I add a password from other apps, like Pages or TextEdit?

Yes. The Print dialog on a Mac can save a password-protected PDF from almost any app that prints. This is handy when your document isn't a PDF yet.

1. Open the document in the app you're using.
2. Choose File → Print.
3. Click the PDF button, or open its menu and choose Save as PDF.
4. Enter a file name and choose where to save it.
5. Click Security Options and set the passwords you want.
6. Click Save.

According to Apple's Save as PDF guide, Security Options can require passwords for opening the document, copying from it, and printing it. That's a nice bonus: you turn a document into a PDF and lock it in one pass.

What makes a good PDF password?

A good PDF password is long and easy for you to remember. Length matters more than odd symbols.

The US National Institute of Standards and Technology (NIST) says this clearly in its Digital Identity Guidelines, SP 800-63B. It sets a minimum of 15 characters for a password used on its own. It also tells systems not to force mixes of character types. Those rules were written for login systems, but I think the length advice is a sound rule of thumb for a PDF too.

• Use a short phrase. Four or five random words, like a silly sentence, are long and easy to type.
• Don't reuse a password from your email or bank.
• Save it in a password manager. A PDF has no "forgot password" button.
• Send it separately. If you email the PDF, share the password by text message or a phone call, not in the same email.

Where does Preview get slow?

Preview handles one file well. It gets slow when you protect files every week or in batches.

• One file at a time. Ten invoices means ten exports, each with the password typed and retyped.
• A hidden button. The password setting sits behind Permissions in the Export window, which is easy to forget between uses.
• Typos. Typing the same password over and over is where mistakes creep in. Check each file opens with the password you meant to set.

How do I protect PDFs faster with FinderBuddy?

FinderBuddy adds Protect PDF to Finder's right-click menu. You pick a password and anyone opening the file will need it.

1. Select one PDF, or several, in Finder.
2. Right-click and choose FinderBuddy → Protect PDF.
3. Type the password you want to set.
4. The protected copy is saved next to the original, which is never changed.

Files are processed on your Mac and nothing is uploaded. The free download includes a limited set of tools, and Protect PDF unlocks with a one-time license. FinderBuddy needs macOS 14 or later on an Apple silicon Mac. If it's your first time, the setup guide takes about a minute.

What this means for you

A password is the last step before you share. A few habits make it work better.

• Trim first. Remove pages the other person doesn't need. The guide to splitting a PDF on Mac covers deleting and extracting pages.
• Combine first. If you're sending several documents, merge them into one PDF so there's only one password to share. See how to merge PDFs on Mac.
• Keep an open copy for yourself. Export with a new name, so you're not typing a password every time you open your own file.
• Changed your mind later? The guide to removing a PDF password on Mac shows how to unlock a file you own.

My honest take

For most people, Preview is all you need. I'd use it for the occasional contract or ID scan and never think twice.

I'd reach for a right-click tool when protecting PDFs is part of the job, like sending payslips or client reports every month. And I'd never use an upload site to add a password. It means handing the file to a stranger to keep it away from strangers, which defeats the point.

The takeaway

Password protecting a PDF on Mac is free and quick. Use File → Export → Permissions in Preview, or Save as PDF with Security Options from any app. Pick a long password, save it somewhere safe, and send it separately from the file.

Once you do it once, it becomes second nature. Your private documents will be a lot safer for it.