Paid Apple Developer Program provides access to beta development tools, beta operating system releases, and distribution ability through Apple’s app store. It also allows you to use some of the cloud-dependent features of the platforms, such as iCloud, CloudKit, In-App Purchase, and App Groups.
t isn’t necessary to be a member of the Apple Developer Program if you don’t intend to submit apps to the app stores, or don’t need the cloud-dependent features. We strongly recommend joining, though, if you intend to build apps for any of Apple’s platforms, as the other benefits are substantial:Access to the Apple Developer Forums, which are frequented by Apple engineers and designed to allow you to ask questions of your fellow developers and the people who wrote the OS.Access to beta versions of the OS before they are released to the public, which enables you to test your applications on the next version of the macOS, iOS, watchOS, and tvOS platforms, and make necessary changes ahead of time. You also receive beta versions of the development tools.A digital signing certificate (one for each platform) used to identify you to the App Stores. Without this, you cannot submit apps to the App Store, making a membership mandatory for anyone who wants to release software either for free or for sale via an App Store.
That said, registering for the Developer Program isn’t necessary to view the documentation or to download the current version of the developer tools, so you can play around with writing apps without opening your wallet.