In The Church of Jesus Christ of Latter-day Saints (Mormon Church), the Melchizedek Priesthood holds the authority over spiritual ordinances and blessings as well as the rights of presidency and the governance of the Church.
Elders may perform all the duties of the Aaronic Priesthood, including baptizing, administering, and passing the sacrament, etc. They can also confirm those who have been baptized and confer the gift of the Holy Ghost by the laying on of hands. Elders may conduct meetings and preach the gospel of Christ among the nations.
Ordination to the office of High Priest comes when a man is called into a bishopric or stake presidency or is called as a mission president, high councilor, patriarch, or similar calling of authority. High Priests can perform all the duties of Elders.
The term Patriarch can be used three ways within the Church: to refer to an ancient prophet such as Abraham, to refer to a father who is the head of his family, and to refer to the ordained office within the Melchizedek Priesthood. They are sometimes known as evangelists.
Patriarchs are typically ordained on a stake level. They have the authority to give special blessings, known as Patriarchal Blessings, to worthy members of the Mormon Church. Patriarch are bestowed with special prophetic insight that allows them to give blessings that speak of a person’s future life, as well as their pre-mortal life.
The ordination of a Stake patriarch is carefully considered. A stake president submits a name to the Twelve Apostles, and they carefully and prayerfully consider that person. The patriarch is then sustained (voted for by the members) in stake conference, and ordained.