website: HTML/CSS + Javascript + PHP (or any other backend language like Python, Node.js etc) Or learn a CMS software like wordpress, u can easily build a webs

website: HTML/CSS + Javascript + PHP (or any other backend language like Python, Node.js etc) Or learn a CMS software like wordpress, u can easily build a website using it. (but to customize it to meet your 100% satisfaction, you need to learn the above techs) If you want to be full-stack web developer, u need to learn some web server knowledge, basics, etc. But its okay to not know it. APP: web app: web app can be built by using HTML/CSS + Javascript + PHP (or other back-end language) native app: (those APP in the ios store or Google Play) you have to learn the native programming languages, in Android case, you need to learn Java/Kotlin, in IOS case, you need to learn Objective-C/Swift. That's pretty much it.