If you have two 30 amp power connections you most likely just have 110v onboard. If you have a 220v 50 amp single shore power cord you most likely have a 220 setup but you may or may not have 220 available onboard.
It is very likely that your electric cooktop is 220v. Air conditioner and their pumps are also candidates to run on 220v. In this case there is probably a section of you AC electrical panel dedicated to 220v and one or two other sections for 110v service.
We have two shore power cords 50a 240v and 30a 120v. We've never used the 120v connection. Quite honestly I don't know why or when I would use the 120v cord. The panel has 240v and 120v sections. I suppose if we docked at a marina with only 120v available we could still make coffee and watch tv.