The best app to learn how to code html, c, etc. Is called SoloLearn.
SoloLearn help you to learn html, c, etc.
It teaches you from the basic to the advance and the best part is that is free so you don't need to pay any cent thats great right
Advantages:
You can develope a web page and sell it
You can make profit from it
That is on the playstore is one of the best apps that teach you about how to code and its free
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