Your question is to vague. Because there are many ways to rotate a part, all with different uses, I have to ask why do you want it to rotate. You can assemble it to a datum with a variable angle. When placing a componant you can use the move commands to rotate it. In Pro/Mechanica you can make a mechanism. And in an explode state you can rotate the part.
You could insert the part in the assy by selecting assy>comp>assemble and select the part, then choose the 'move' tab in the dialogue box, afterwards select rotate and as a reference axis select the edge you want the piece rotates around. Then move mouse.