Haw can i made a simple app

Answer 1

Try App inventor or transform a Web program to an App
https://code.sololearn.com/Wx8a6zsqSx9v/?ref=app

Answer 2

Which programming language?
You can do simple apps in almost every programming language, I suppose. You'll probably want something with a GUI...

Answer 3

Do the Swift course on Sololearn.

The second half of the tutorial is all about creating an app

Answer 4

If you are clear with the concepts you can try solving easy Code Coach section in Community tab.