How to make interaction between application and CRM in php?

Question

Android

Applications for android have never been written.
There is a CRM of orders from an online store on a dedicated server.
Managers work in the system under their own passwords.
It took a simple application for managers, authorization, viewing orders, changing status, and the like.
Tell me how do the application and CRM interact in this case?
Is it suitable to write an api script that will give the necessary data on a specific request in json format or the like? (from action: getOrders, from: '2020-06-01', to: '2020-06-30')
Or is it done differently?