Check the Require Set a password for opening the PDF: Select Require Password To Open Document. Tip: To lock or unlock a file in the Finder, select the file, choose File > Get Info, then select or deselect the Locked checkbox Follow the procedure below to print a document using the Locked Print function. Move the pointer next to the document’s name in the title bar, click the arrow that appears, then select or deselect the Locked checkbox. Open the PDF you seek to lock. Click Permissions. Or if