Why does my fuel injected motorcycle have a choke lever?

I have a fuel injected bike, it have a choke lever on left hand side of handlebar. I got various answers like, its for cold start, for controlling air fuel mixture. At what setting should i keep it ? What is the exact purpose? I have a limited knowledge in this area. via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/9v9j62/why_does_my_fuel_injected_motorcycle_have_a_choke/?utm_source=ifttt