publishing apps

Welcome to the forum.

Your question is a bit general, so I understand you want to understand the overall process ?

There are many articles on the web (search for publishing appstore), like this one (dating 2018 but still relevant).

https://medium.com/@the_manifest/how-to-publish-your-app-on-apples-app-store-in-2018-f76f22a5c33a

You need to have Xcode and a paid developer account to publish.

Then build your app and download on appstoreConnect.

Don't hesitate to ask if you have specific questions. Otherwise, don't forget to close the thread by marking the correct answer.