Build me a app

I need an app for ios and android.. i am a owner of study&play ground for kids. We have approx 30 members for now. I need an app for our members to create an account/profil and make their payment to our bank account via app.they will buy package subscription for exp 10/20/ 30 lesson.when they join the lesson for exp 20 lesson will update as 19 lesson. I will add screenshots for you..