Method 1: On Mac (Using Preview)
macOS includes incredibly robust PDF manipulation tools right out of the box. You do not need Adobe Acrobat.
- 1
Double-click your PDF to open it in Preview.
- 2
Click File in the top menu bar, then select Export.
- 3
Check the box that says Encrypt.
- 4
Type your strong password twice to verify it, then click Save. The resulting file will show a lock icon in Finder.
Method 2: On Windows (Using Microsoft Word)
Windows doesn't have a native PDF encrypter built into the OS, but if you have Microsoft Word installed, you can use it to create protected PDFs.
- Open the document in Microsoft Word.
- Go to File > Export > Create PDF/XPS Document.
- Before clicking Publish, click the Options button.
- Check the box that says "Encrypt the document with a password" and hit OK.
- Enter your password and publish the PDF.
Frequently Asked Questions
Can a password-protected PDF be hacked?
It is extremely difficult. Modern PDF encryption uses 256-bit AES encryption (military-grade). If you set a strong, long password, it would take supercomputers millions of years to brute-force crack it. However, if your password is '12345', it can be unlocked instantly.
Do I need to pay for Adobe Acrobat to encrypt a PDF?
No! Mac users can do it entirely for free using the built-in Preview app. Windows users can use free open-source software like PDFCreator, or use secure browser-based tools.
Can I remove a password from a PDF later?
Yes, but only if you know the password. If you open the protected PDF in Mac Preview or Chrome, type in the password, you can simply choose to 'Export' or 'Print to PDF' again without enabling encryption, which will save a new, unlocked version.