It is a good idea to secure a file that contains sensitive information. This helps prevents that information from falling in the hands of those with bad intentions.
This knowledge article demonstrates how to encrypt an Adobe Acrobat Pro file.
Step 1
Access the All tools pane in Adobe Acrobat Pro by opening a desired PDF file and click on the All tools menu option.
Step 2
Click on the Protect a PDF option from the list.
Step 3
Click on the Encrypt with Password. On the pop-up window "Applying New Security Settings" select Yes
Step 4
Select the Require a password to open the document check box, enter a strong password, and then click OK.
Step 5
On the pop-up window "Confirm Document Open Password," re enter the current password, click OK
Step 6
On the next window "Acrobat Security" click OK
Step 7
Go to Menu to Save and Close the file. Next time when you access the file, you will be prompted to enter the set password for the file.
NOTE: If you forget the password, the file will not be accessible for use. Therefore, save the password in a safe location.