BMW does not yet support Android Auto or Apple CarPlay on any model.
Getting those integrated into a current i3 sounds difficult. It would have to be some kind of module that plugs into the brains of the multimedia computer under the rear seat since there is no "head unit" on the dash anywhere to replace.
Basically options are zero unless you want to strap a tablet over the top of the control display.
2017 REx - Platinum Silver - Deka