PDF files, or "Portable Document Format" files, are a type of document created to allow documents to be displayed a certain way regardless of the computer or device from which they are being read. They can be viewed on many devices in a variety of programs, and can be read and edited as the user sees fit. It is also possible to "lock" a PDF file to make it essentially read-only, allowing users to read the file, but not permitting any changes to be made. The encryption process is simple and requires only access to your PDF file in Adobe Acrobat Reader.
Open your PDF file in Adobe Acrobat Reader. Click on "Advanced," then "Security," then "Encrypt With Password." Click "Yes" on the dialogue box that appears.
Select "Encrypt all document contents" and "Require password to open document," then enter the password you want the document to be accessible with in the "document open password" input field. Edit the options to allow or restrict editing and printing.
Disable the copying of text, images and other content, double check all your settings, then click "OK." Verify the passwords you have entered on the document, then accept the prompt that appears after that.
Test the PDF file by opening it on another account or computer.
Getting around locked PDF files can be relatively simple, so be aware that locking your PDF file will not be a foolproof way to prevent the copying of content.