How to generate app store uploadable files?

Archive and upload your app using Xcode

Before you can submit your app for review through App Store Connect, you need to upload the build through Xcode.
In Xcode, select Generic iOS Device as the deployment target.
Choose Product from the top menu and click on Archive.
The Xcode Organizer will launch, displaying any archives you’ve create.
Make sure the current build is selected and click on Upload to App Store in the right-hand panel.
Select your credentials and click Choose.
In the next window that appears, click on Upload in the bottom right-hand corner.

A success message will appear when the upload has been completed. Click Done.