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 wish to make a joint pinned for a truss situation, then you can use the Joint Type command to do so. 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 only wish to release the moments at the ends of some of the members connected to a joint, then you should use the Member Type command. In the Member Type dialog 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 releases at the end of a member when you want to have a frame where a part of the frame is pinned and the remainder is rigid. This is common when you have a continuous top and bottom chord in a truss, and you just wish to apply member releases to the bracing members between the chords.
 
You should not pin a joint and also pin the end of a member attached to that joint.