There are several ways to deploy an iOS app. Here is when to use them.
- TestFlight: Apps can be reviewed inside the testflight app. Apps must pass checks upon upload (No deprecated APIs for example).
- Public: Can be used for up to 10 000 users. Apps must be reviewed by Apple. You can either do this over email, or through a public link.
- Internal: Can be used for up to 25 people. These must all be part of your iTunes connect team.
- Ad-hoc: You only need the device ID of the users, and they will be able to install via a link.
- Enterprise: Used for deployment in an organization. Can create a link that allows anyone inside the organization to install.
- Development: Test with members within team. Can create link for installation.