The diagram for crate A has all the forces acting on crate A. This would be a horizontal applied force to the right, a horizontal normal force from crate B to the left, a vertical gravitational force downward, and a vertical normal force from the supporting surface upward.
The diagram for crate B has all the forces acting on crate B. This would be a horizontal normal force from crate A to the right, a vertical gravitational force downward, and a vertical normal force from the supporting surface upward.
There are two things to remember if you are going to use these diagrams to solve a problem. The horizontal normal forces from each crate on the other are equal in magnitude (Newton's Third Law). And since the crates move away together, they must have the same acceleration.
