Which language is the most important for an entrepreneur and what should they mostly focus to make their career in IT ?

Answer 1

Hello there !
First of all an entrepreneur is someone who is good at buying and selling products they don't know much about programming.
If you are a beginner in programming and want to learn then I would recommend you to learn web development first.
Things you need to learn
● HTML
● CSS
● JAVASCRIPT
Source to learn
● W3schools.com (recommend)
● Sololearn
Hope this helps you

Answer 2

This depends a lot on which product you are going to build

Answer 3

NoOr is very right!
Do start by deciding what you want to build... that will save you a whole lot of time and resources.