The default behavior of Multiframe in regards to pinned and fixed joints and members is that all members and all joints are initially fully rigid. This means that there is complete moment transfer across each joint. If you make a joint pinned, then this releases the moments and torsion at the ends of all the members attached to that joint. It also sets the rotations of that joint to zero.
 
If however you release the moments at the end of a member using the Member Type command, then in the Member Type dialogue you have an option of which moments and torsion to release.
 
In general you will want to use a pinned joint when analyzing a truss structure and you will want to use the pins at the end of a member when you want to have a rigid frame where a part of the frame is pinned.
 
You should not pin a joint and also pin the end of a member attached to that joint.
 
Also keep in mind that releasing moments on a member releases the local rotations and moments whereas applying a pinned joint restraint releases the global rotations and moments.