iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. Exclusively for its hardware. It is the operating system that presently powers many of the company’s mobile devices, including the iPhone, iPad, and iPod Touch. It is the second most popular mobile operating system globally after Android.

Initially in 2007 iOS has been extended to support other Apple devices such as the iPod Touch and the iPad. As of January 2017, Apple’s App Store contains more than 2.2 million applications, 1 million of which are native for iPads. These mobile apps have collectively downloaded more than 130 billion times.

The iOS user interface is based upon direct manipulation, using multi-touch gestures. Interface control elements consist of sliders, switches, and buttons. Interaction with the OS has specific definitions within the context of the operating system and its multi-touch interface.