The SAMSUNG Mobile USB Composite Device driver is used to allow your Windows computer to communicate with Samsung mobile devices (such as smartphones or tablets) when connected via USB. The driver facilitates a range of functions, such as file transfer, charging, and device management (including syncing contacts, photos, and media). It's typically required for devices that use Samsung Kies or Samsung Smart Switch for syncing data, or when you want to use your phone as a media device or for debugging purposes with Android development tools.