How to Password-protect an Existing PDF

By Anthony Thompson

Portable document format, or PDF, files are a great way of sharing information across the Internet. If you have a full version of Adobe Acrobat, you can password-protect your PDF files so that unauthorized users are unable to access them. You can then send sensitive or personal information by email, safe in the knowledge that only you and those to whom you have given your password will be able to access the files.

Things You'll Need

  • Adobe Acrobat

Step 1

Double-click on the PDF document that you wish to secure with a password to open it using Adobe Acrobat.

Step 2

Select "Secure" from the taskbar menu.

Step 3

Select "Password Encrypt" or "Encrypt with password" from the drop-down menu -- the exact wording will depend on which version of Adobe Acrobat you are using -- and click "Yes" on the confirmation dialogue box to bring up the "Password Security Settings" screen.

Step 4

Choose which earlier version of Adobe you wish your document to be compatible with from the list of options at the top of the menu box.

Step 5

Click the "Require a password to open the document" check box. Choose your password and type it in.

Step 6

Click the next check box to choose whether to allow people to print or make changes to your document. If you choose to allow these privileges, you will need to add a second, separate password. If you are happy to allow some printing and editing options, choose them from the drop-down menus.

Step 7

Click "OK" to save your changes. Your document is now protected with a password.

Tips & Warnings

  • You need Adobe Acrobat to create secure PDF files, but you can use the free Adobe Reader program to view them as long as you have the right password.
  • Older versions of Adobe Acrobat may require you to use a different method to password-protect a PDF file.
  • Record the password or choose one you can easily remember; otherwise, you will lose all access to the file.