A profile is used to display various information about a resident in the profile window. A profile will always contain the resident's name, "born" date, account type and partner. Other information can be left blank by the resident.
There are many ways to view a profile. If the resident is not a friend, or their calling card is not in inventory, search for their name in the find window (under "People") or right-click their avatar and select "Profile" from the pie menu. If the resident is a friend, or their calling card is in inventory, open the friends window and select the resident, or double-click their calling card.