I've only recently started to delve into how building apps work. I'd like to know what the general setup is for a mobile app and a website, in which users can update information on the app through the website. 

I'm trying to learn how to make an iOS app with Swift, and use Amazon Web Services as the backend for it. If I wanted to then make a website that would change data on the mobile app, would I have to create a website from scratch with Ruby or Python, and then somehow connect that to the same AWS backend that my iOS app uses? 

Thanks.