A mobile operating system (OS) features a user-friendly interface, touch screen support, and versatile app management. Key characteristics include multitasking capabilities, support for various hardware configurations, and connectivity options such as Wi-Fi, GPS, and mobile networks. Security features like app sandboxing and permissions are crucial for safeguarding user data. Popular mobile OS examples are Android and iOS, each offering a unique ecosystem for developers and users. Overall, mobile OSs optimize performance and battery life while providing essential functionalities for users on the go.