Changing the gasoline

Hi

I am having 2017 Honda City. Till now i'm using E85 gasoline for this car. Is it okay to go for E20 because I heard that it will give better mileage when compared to E85, Now I am getting mileage of 10-12kms/ltr. If I can change it, how to change it, what is the procedure and guidelines I need to follow before and after changing it.

Thanks

New topic