Some places in Tahiti will accept USA currency however most places in Tahiti do not accept US dollars so it's recommended to exchange your USA currency or USA dollars into money that is accepted more widely in Tahiti.
You can exchange your USA dollars or USA currency for Tahiti currency at any bank in Papeete or at the Tahiti International Airport.
So that's what I would recommend you do before planning to use money in Tahiti so that you know your money will be accepted.