If your only talking about the app store then you program your app and when it is finished you submit it as an Apple developer and pay $99 for the app to be up.
Steps of what to do for submitting to the App Store:
Assemble App Store Information.
Create a Bundle Identifier.
Create a Certificate Signing Request.
Create an App Store Production Certificate.
Create a Production Provisioning Profile.
Create an App Store Listing.
Make The Release Build
Fill In Version Information
Submit Version For Review
Release
hope that helps you out homie and good luck on your app bro.
