iOS stands for "iPhone Operating System" and is a mobile operating system developed by Apple Inc. exclusively for its hardware, including the iPhone, iPad, and iPod Touch devices. It is responsible for everything that goes on on these devices, including making phone calls, sending text messages, taking pictures and videos, running apps like Facebook, TikTok, or Instagram, browsing the Internet, sorting out settings, and more. iOS is based on Macintosh OS X and supports Objective-C, C, C++, and Swift programming languages. It features an intuitive user-centered design and the ability for app developers to create apps, distributed through the iOS app store. As of 2023, the Apple iOS market share was 19.9% worldwide, according to IDC.