You add a main Personal Folders as a service to the User Profile and give it a file name.
Personal Folders have a .pst extension.
For Microsoft Mail Post Offices, a Personal Folders is set up automatically because the Inbox and Outlook folders reside there. The Personal Folders file contains folders, messages, forms, and files. You can also designate a Personal Folders file as the delivery location for your incoming messages. In the Service s dialog box, click the Delivery tab. If you set up a computer to use Remote Mail, you must click the name of a personal folder file.