MapKit is a software framework developed by Apple that allows developers to integrate maps into their applications for iOS, macOS, and watchOS devices. It provides a range of features such as displaying maps, marking destinations, and creating routes. MapKit utilizes data from various sources including Apple Maps, Bing, and OpenStreetMap to provide accurate and detailed maps to users. The framework also allows for customization of the visual appearance of maps and the addition of annotations and overlays.