Build me an android app(supports all android mobiles)

I want a digital wallet app with mobile otp based registration and login and with the features of load Money, Send money to another wallet(registered mobile no) , bank account(bank account details saving option) and most importantly every time Customer can load money to their wallet he can earn some points, and reward points to convert cash and customer support also. with the Price and how many days it will take for Developing(razorpay payment integration)