How to create an app?

Question

how many languages were used ?

Answer 1

It really depends on what app you’re creating.
From your tag you might be interested in learning the HTML+CSS+JS bundle. Studying the SoloLearn courses together with other resources you could obtain online (MDN etc.) you should be ready to make a basic web page to an addictive web game.

Answer 2

Of course there are pre-made frameworks out there that might save you some time, but SoloLearn might not provide courses on those. (maybe you could help creating lessons)