The U.S. uses two types of elections that implement Ranked Choice Voting (RCV) in different ways.
When used as an "instant runoff" to elect a single candidate like a mayor or a governor RCV helps elect a candidate that better reflects the support of a majority of voters. When used as a form of fair representation voting to elect more than one candidate like a city council, state legislature or even Congress, RCV helps to more fairly represent the full spectrum of voters.
Read below for more information about how these elections work