I want to built an e-commerce app. Which programming language I should learn step by step?

Question

Guideline to create an app

Answer 1

For a web app you can learn any of these JavaScript, Python, PHP

For Mobile App you can learn JavaScript, Java, Kotlin or Swift.

Javascript will be the most important for you.

Frontend-JavaScript
Backend-JavaScript, PHP, Python, .Net, Java, etc there are others as well.

In the end it all depends on you and your needs.