Bishops, Priests anmd Deacons. The Pope is a Bishop, The Bishop of Rome the Successor of St. Peter. Cardinals are Bishops.
Priests are in charge of a parish or several parishes.
Sometimes other places like schools , Etc. Msg. is a Priest of distinguished service. Deacons assist the Bishop and Priests. Secular Priests and Deacons serve a Bishop. Religious Priests and Deacons serve in an Order and live under a rule.