A force can change things.  Push and pull are forces.  A force can start, change and stop things.

Put energy to make something go farther away.  This is called to push.  We can push a shopping cart, or a ball, or a. baby carriage.

Pull means to bring something towards one.  This is a force.  This is called to pull.  We can pull a wagon.

Forces can change things.  A ball is stopped.  We kick it.  Now it is moving.  We catch a moving ball.  Now it is stopped.  We bat a ball and it changes directions.  These are all changes.