iOS is the operating system used by Apple on the iPhone, and its full name is iPhoneOS.

Apple first announced the iOS system at the Macworld conference on January 9, 2007. It was originally designed for iPhone, and was later applied to iPod touch and iPad.

iOS, like Apple's macOS operating system, is a Unix-like commercial operating system. Originally this system was called iPhone OS. Because iPad, iPhone, and iPod touch all use iPhone OS, it was announced at the 2010 Apple Worldwide Developers Conference that it was renamed to iOS. iOS is a registered trademark of the network equipment operating system of Cisco Systems in the United States. Apple has obtained the Authorized by Cisco.

iOS has the most applications of any mobile operating system. The iOS platform has a huge number of mobile apps, with thousands of apps in almost every category. And every app is inherently great. That's because Apple provides third-party developers with a wealth of tools and APIs so they can design apps that take full advantage of the advanced technology contained in every iOS device. All apps are in one place and can be easily accessed, searched and purchased using your Apple ID.

Built-in iOS apps

Siri: Siri in iOS has a new look, new voice, and new features. Its interface has been redesigned to fade into view and appear on top of any screen. Siri answers questions faster and can query more information sources, such as Wikipedia. It can take on more tasks like returning calls, playing voicemails, adjusting screen brightness, and more.

FaceTime: With just one tap, you can use your iOS device to make video calls with others over Wi-Fi or 4G, or even FaceTime friends over cellular on your iPhone or iPad call. Although it is far away, it feels like it is close at hand.