Smartphone apps are software applications designed to run on mobile devices like smartphones and tablets. They can be downloaded from app stores, such as the Apple App Store for iOS devices or Google Play Store for Android devices. Apps serve various purposes, including communication, entertainment, productivity, and education, making it easy for users to access information and services on the go. These applications can be free or paid, and many offer in-app purchases for additional features. Popular examples include social media apps like Facebook and Instagram, as well as navigation apps like Google Maps. Overall, smartphone apps enhance the functionality of mobile devices and improve user experience.