In addition to rhythm slashes to indicate improvisation, you can use bar repeats as a short-hand to tell players to repeat what they did in the previous bar.
Procedure
Result
You have input bar repeat regions for single bars on both piano staves.
Tip
You can also add bar repeat regions using the Repeat Structures panel on the right of the window, which you can show by clicking Panels , then Repeat Structures in the Notations toolbox.