When ordering a Jitterbug phone, you can pre-populate the contact list. If ordering the one touch, you can also specify which contact number should be assigned to the center key and how it should be labeled. Each contact entry can only store a name and one phone number, so multiple entries for the same contact will show up separately.
You can add your own contacts to the list by scrolling to the end of the list and selecting new entry. This can even be done on the one touch handset because names and numbers are entered by scrolling up and down and pressing yes to confirm. Users with the dial handset can press the actual keys to quickly enter a number or scroll to the first letter for that key when entering a name.
Scrolling to the end of the contact list and then choosing no will bring up a menu that allows you to modify or delete existing contacts.