How to become a application developer

Question

How many languages should I know to develop a app?

Answer 1

I think the following are some of the best programming languages for App + other things:
- Python
- C++
- Swift (iOS, Mac ..Apps).
umm, ... and i think JS too.

Answer 2

Swift??

Answer 3

To develop a mobile app you have knowledge of react native, flutter, Android, ionic any one of them it's depend upon your interest what kind of mobile you wanna to make and how scalable this one .