A smartphone app is a software application designed to run on mobile devices like smartphones and tablets. These apps can perform a variety of functions, from social networking and gaming to productivity and navigation. Users can download apps from platforms such as the Apple App Store or Google Play Store. Smartphone apps are typically user-friendly and provide quick access to information and services. They often utilize the device's features, such as the camera, GPS, and touch screen, to enhance user experience. Many apps are free, while others may require a purchase or subscription for additional features.