How do I get the FullName of the current user that is logged in?

The user logs into the system. The system looks up the userid and password and validates them. The user enters into the system.

I assume that the User information is available somehow. Is the fullname stored as a Session variable? Do I need to pull the name from the table again via the UserPK?

I would like to store the User Name on the records that they create (Client Request).