The game comes directly from Nintendo eShop, you will be able to go online, get updates etc.
After setup process the game will be available to launch on your own account, just as any other game or app you purchased directly in Nintendo eShop.
Hit the road with the definitive version of Mario Kart 8 and play anytime, anywhere! Race your friends or battle them in a revised battle mode on new and returning battle courses. Play locally in up to 4-player multiplayer in 1080p while playing in TV Mode. Every track from the Wii U version, including DLC, makes a glorious return. Plus, the Inklings appear as all-new guest characters, along with returning favorites, such as King Boo, Dry Bones, and Bowser Jr.!