A typical RPG launcher fires a rocket out of a tube. The launcher rests on the firer's shoulder. The rocket is percussion fired with the exhaust from the propellant charge exiting the open rear end of the firing tube. Just as the rocket emerges from the tube, stabilising fins spring out from the rocket. These fins along with a motor on the rocket allows the missile to travel up to 5 km with a little accuracy.
The weapons were developed during WW II, the US Bazooka? and the German Panzerfaust? being two famous examples.