When designing the process flow of your process, you can execute another process. Your process flow waits for the executed process to end its execution before following on into the next process activity in the path. This behavior is implemented through the Execute Process process activity which you can drag onto your canvas from the Process Flow Toolbox.
The use of the Execute Process allows you to improve the reusability of processes and help you to maintain consistency in the implementation of processes.
An Execute Process has the input parameters and output parameters of the executed process.
Execute Process Properties | Process Flow Toolbox