Simple coordination exercises with racket and ball are suitable for tennis beginners:

Balance the ball on the racket (in motion).
Balance the ball at eye level on the racket (in motion).
Push the ball up from the bottom to the top with the forehand face of the racket.
Push the ball up from the bottom to the top with the backhand face of the racket.
Push the ball up from the bottom to the top alternately with the forehand and backhand faces of the racket. After each pass (forehand/backhand), optionally play the ball upwards once with your free hand.
Bounce the ball upwards with the forehand face of the racket (without the ball hitting the ground).
Bounce the ball upwards with the backhand face of the racket (without the ball hitting the ground).
Bounce the ball upwards alternately with the forehand and backhand faces of the racket (without the ball hitting the ground).
Bounce the ball upwards twice with the racket, let the ball hit the ground and bounce it upwards twice again.
Bounce the ball upwards with the racket, after a few touches try to play the ball upwards with the frame.
Bounce the ball downwards (in motion - always keep the racket above the ball).

With partner:

Player 1 plays the ball upwards, the next ball is played upwards by the partner.
Player 1 plays the ball upwards, the partner lets the ball hit the ground before playing the ball upwards.
Player 1 bounces the ball, the next ball is bounced by the partner.
2 players pass the ball to each other along a line, but the ball is first caught with the free hand before being returned. In the first phase, let the ball hit the ground and pass it back, then pass the ball directly from the air to your partner.
2 players pass the ball to each other along a line (forehand/backhand/alternating forehand and backhand).