A: For distribution of alpha, beta, or enterprise builds on iOS, you do need to enroll for Apple’s developer program. There are two different programs available:
The Apple Developer Program lets you distribute your apps through the App Store and for testing purposes through ad-hoc distribution. This kind of distribution is limited to 100 UDIDs per device type (iPhone, iPod, iPad, Apple Watch, and Apple TV).
The Apple Developer Enterprise Program is intended for in-house distribution of your enterprise or line-of-business apps without the need of collecting UDIDs. It cannot be used to submit apps to the App Store.
Please note that it is your responsibility to comply with Apple’s terms and conditions.