From the Catechism of the Catholic Church (CCC, 1536):
Holy Orders is the sacrament through which the mission entrusted by Christ to his apostles continues to be exercised in the Church until the end of time: thus it is the sacrament of apostolic ministry. It includes three degrees: episcopate, presbyterate, and diaconate.
The Cathedral church, as the mother church of the diocese, is the typical place for the celebration of ordinations. If you are discerning a vocation to the priesthood or diaconate, contact the diocesan vocations office (573) 635-9127, the office for the permanent diaconate (573) 635-9127, or speak with one of the priests or deacons at your parish.