How yo create app?

Answer 1

Web app - HTML/CSS/JS + SQL/PHP
Android - Java/XML + SQL
iOS - objective C + SQL

Just examples - you might as well use the Xamarin package and have it all done in C#

Answer 2

https://www.sololearn.com/discuss/283660/?ref=app
https://www.sololearn.com/discuss/349523/?ref=app
https://www.sololearn.com/discuss/349613/?ref=app
https://www.sololearn.com/discuss/358124/?ref=app
https://www.sololearn.com/discuss/243970/?ref=app
https://www.sololearn.com/discuss/347474/?ref=app
https://www.sololearn.com/discuss/360020/?ref=app
https://www.sololearn.com/discuss/136909/?ref=app
https://www.sololearn.com/discuss/356676/?ref=app
https://www.sololearn.com/discuss/175847/?ref=app
https://www.sololearn.com/discuss/82769/?ref=app
https://www.sololearn.com/discuss/242006/?ref=app

... And the list goes on. I strongly advise you to look it up here in the Q&A, it is a common question, and there are lots of great answers already.

Answer 3

if u r talking about android apps. you need too learn java and xml and then you can code your app.