Note that the 3 BSD operating systems use CHPASS to do these functions.
chfn - Changes your Finger information (i.e. - Full Name, address, phone, ...)

chfn displays prompts for entry of your finger information as follows:
Office Phone[]:
Home Phone[]:

The brackets contain the current information. Just press to accept the current data, type in new data and press , or type in the keyword none and press to delete all data from that item.

chfn -f only requests your name
-o, -p, -h do the same for Office Room Number, Phone Number (Office), and Home Phone Number

The file /etc/passwd contains a list of users, UID's and user information, including the home directory and all the finger information.

see finger to view a user's finger information