Two modules are required:
Client(User) Module and Admin Module
Client should be able to set a appointment with a trainer(Select a specific trainer from many trainer available) .
The appointments which are set should be visible in a Calendar to the User as well as Admin which shows the appointment time and name of trainer.
The Trainer should be able to set his/her User's Diet Plan(Diet Plan may change after a specific amount of duration)
Admin must be able to send Invoices to User Via App
Developer must be comfortable in Hindi