The iOS Developer Program is Apple's fee-based subscription that allows members to publish apps for devices based on the company's mobile operating system to the app store.
IOS-based devices include the iPhone, iPad and iPod Touch. However, subscribers to the iOS developer program have the tools and options to publish apps for all of the company’s platforms because Apple combined Mac, iOS and Watch OS developer memberships into the Apple Developer Program.
Apple provides tools and resources for creating iOS apps and accessories for these devices. As an iOS developer, you can program in native languages such as Swift or Objective-C or build cross-platform native applications using React Native (JavaScript) or Xamarin (C# & F#).