The Apple App Store is a digital application distribution platform for iOS developed and maintained by Apple Inc. The service allows users to browse and download applications from the iTunes Store that were developed with the iOS SDK published through Apple Inc.
Depending on the application, they are available either for free or at a cost. The applications can be downloaded directly to an iOS device, or downloaded onto a personal computer (PC) or Macintosh via iTunes. iOS Application Development is the process of creating small software applications for iPhone devices.