smartform design?

when we are calling smartform with driver program and passing form interface parameters in function module genarated by smartform is it mandatory to declare internal table in bcz we already passing data data

     1.  Global settings :

           Form interface

           Variable name    Type assignment   Reference type

           ITAB               TYPE                  Table Structure

    2. about looping is it mandatory at form level or we can do looping in driver program.