How does the velocity, the distance it has fallen and the acceleration of a free falling body change with time?

The acceleration a free falling body experiences due to gravity will always remain the same. It will always be - 9.8 m/s^2.

Thus, the downward velocity of the body will always be increasing (or decreasing, however you want to think about it) because gravity is acting upon it.

The distance the body has fallen will increase faster and faster over time because its velocity is increasing.