Xamarin is a cross-platform development tool that allows developers to create native apps for Android, iOS, and Windows using a single shared codebase. Xamarin apps are written in C# and compiled to native code, allowing them to access device-specific features and performance.
For example, a Xamarin developer can create a single app that can be used on both Android and iOS devices. The app could use the same codebase for both platforms, but also take advantage of platform-specific features like camera access, GPS, and more. The Xamarin framework also allows developers to create custom UI components, allowing them to create a unique look and feel for their apps.