It depends how the beam is fixed. If it is 'simply supported' then yes, fixed geometry to one end face or both would be used.
That's a somewhat vague question; can you give the full context of the problem? Simply-supported typically refers to a pin-constraint on one end and a roller-constraint on the other.
please include context to your question as requested by others
but generally it would be fixed on one end and then on the other roller slider. but you have to be careful based on element selection as well because you want to allow rotation.
if you are comparing to hand calcs, make sure that you know the assumptions they make. ie things like infinitely small contact areas..etc.