Open the PDF in Adobe Acrobat
Go to File
Select Properties
Open the Security tab
Choose Password Security from the Security Method menu
Check Require a password to open the document
Enter the desired password
Confirm the password
Click OK
Save the PDF
Open the PDF in Microsoft Word if it is editable
Go to File
Select Save As
Choose PDF as the file type
Click Options
Enable encrypt the document with a password if available
Set the password
Save the file
Use an online PDF password tool
Upload the PDF file
Choose the option to add a password
Enter the password
Download the protected PDF
Use a PDF editor or printer utility with security settings
Open the PDF
Select the password protection option
Enter and confirm the password
Save the protected file