Hello!
Orbital motions are the result of the balance between the forward motion (its direction will be related to a reference point) of a body in space (like planets, moons) and big size (and mass) body.
The gravity pulls the small size body to the big one, as result, the speed of the small body and the gravity of the big size body creates a perfect balance, describing what we call an orbit.
The small size body is always trying to move forward while the gravity of the big size one attracts it when the balance is perfect, it creates an endless cycle (orbit)
If the balance is not perfect, for example, if the speed of the small size body is too high, the body will continue its forward movement and there will not be an orbit. On the opposite side, if the big body size is too big, the gravity will attract it completely and crash.
Have a nice day!