iPhone is a line of smartphones designed and marketed by Apple Inc. They run Apple's iOS mobile operating system. The first-generation iPhone was released on June 29, 2007, and there have been multiple new hardware iterations with new iOS releases since. The user interface is built around the device's multi-touch screen, including a virtual keyboard. The iPhone has Wi-Fi and can connect to cellular networks. An iPhone can shoot video (though this was not a standard feature until the iPhone 3GS), take photos, play music, send and receive email, browse the web, send and receive text messages, follow GPS navigation, record notes, perform mathematical calculations, and receive visual voicemail. Other functionality, such as video games, reference works, and social networking, can be enabled by downloading mobile apps. As of January 2017, Apple's App Store contained more than 2.2 million applications available for the iPhone.
The original first-generation iPhone was a GSM phone and established design precedents, such as a button placement that has persisted throughout all releases and a screen size maintained for the next four iterations. The iPhone 3G added 3G network support, and was followed by the 3GS with improved hardware, the 4 with a metal chassis, higher display resolution and front-facing camera, and the 4S with improved hardware and the voice assistant Siri. The iPhone 5 featured a taller, 4-inch display and Apple's newly introduced Lightning connector. In 2013, Apple released the 5S with improved hardware and a fingerprint reader, and the lower-cost 5C, a version of the 5 with colored plastic casings instead of metal. They were followed by the larger iPhone 6, with models featuring 4.7 and 5.5-inch displays. The iPhone 6S was introduced the following year, which featured hardware upgrades and support for pressure-sensitive touch inputs, as well as the SE—which featured hardware from the 6S but the smaller form factor of the 5S. In 2016, Apple unveiled the iPhone 7 and 7 Plus.