How to Password Protect a PDF

You need to send a PDF that only the recipient should be able to open. Preview, Word, and Adobe's online tool all add an open password with no paid software.

Export with a password from Preview on Mac

Open the PDF in Preview and choose File, Export. Keep Format set to PDF. On recent versions of macOS, click Permissions, tick Require Password To Open Document, and type the password twice. On older versions, tick Encrypt and enter the password. Click Save with a new file name so the original stays unlocked.

Set permissions if you want to limit printing or copying

In the same Permissions sheet, an Owner Password section lets you block printing, copying text, and editing. Set a separate owner password there. These restrictions are advisory, as explained in the note below.

Save from Word with encryption on Windows

If the PDF starts as a Word document, choose File, Save As, set Save as type to PDF, and click Options. Tick Encrypt the document with a password, click OK, type the password twice, and click Save. The Mac version of Word does not offer this option, so use Preview there.

Use Adobe Acrobat online on Windows without Word

Go to adobe.com and open the free Protect PDF tool. Upload the file, type a password, confirm it, and download the protected copy. Sign in with a free Adobe account if prompted.

Test the file before sending

Open the new PDF. It should ask for the password before showing any page. If it opens straight away, you saved the wrong copy.

Send the password separately. Emailing the password in the same message as the file defeats the point. Send it by text message, say it on a call, or use a password manager's sharing feature.

Only the open password protects content. A permissions password that blocks printing or copying can be stripped in seconds with free tools, and many viewers ignore it entirely. Treat it as a polite request, not security. Web tools upload your file to their servers, so for anything truly sensitive use Preview or Word instead.