In addition to the basic contact information, you can add in other information. These include Source, Affiliation, Job, Priority, and Status by default.
You can choose which information appears here or add your own lists by customizing it in the Tools Menu > Options > Custom Fields.
The first four of the custom fields (Source, Affiliation, Job and Priority by default), use drop-down menus which are based on the options that you decide in the Custom List Setup.
If this contact was referred by someone on the referral list, choose that name in the referred by drop-down menu. If the contact was referred by someone else, you need to first add that person to the referal list. For information on adding someone to the referral list, see contact information.