What should I study to develop a mobile app.?

Hi, You can attend mobile app development workshops, which generally happen in colleges. Or, you can attend a seminar or stuffs, which may help you develop then. I think, you specifically don't need to do any course.

Hi there, you can opt for Computer Science Engineering or Information Technology to learn the basics of app development. And, it is not mandatory to join these. Nowadays, various tutorials and books are available that teaches you app development from the basics. All the best.