Consider a ball placed at a height. It will have only potential energy and no kinetic energy.
If the ball is released from the height, it falls down and the vertical height of the ball from the ground decreases. Therefore, the potential energy decreases and it changes to kinetic energy due to which the speed of the ball increases. During the fall, the ball has both the potential energy and the kinetic energy. As the ball reaches the ground, the potential energy becomes zero and it changes entirely into kinetic energy.
The below figure shows the conversion of potential energy into kinetic energy during the vertical free fall of a ball at various positions A, B and C.
