Only 1 player is possible offline; a local two-player mode is not specified. Up to 8 players are possible online, but there is no confirmed multiplayer mode offline.
The game comes as a physical card for the Nintendo Switch, not just a download code. However, it requires an additional download of about 2GB to play, as the cartridge contains only part of the game data. This is typical for many Switch games that include extra content or updates.