In the USA a marriage officiant is a civil officer such as a justice of the peace who performs acts of marriage or civil union. Their main responsibility is to witness the consent of the intended spouses for the wedding license and hence validate the marriage or civil union for legal purposes.
Religious
Religious weddings are officiated by clergy people:
The officiant's duties and responsibilities, as well as who may be an officiant vary among jurisdictions.
By country
United States
In the United States, Canada and several other countries around the world, a celebrant is a person who performs religious or secular celebrancy services for weddings, funerals, child namings, coming of ageceremonies, and other rituals. Most celebrants are ordained clergy, while some are legal officials. In Humanist weddings, a Humanist officiant presides. Celebrants may perform alternative and nontraditional ceremonies in places, and under circumstances where mainstream religious clergy will not. Some celebrants perform same-sex weddings and commitment ceremonies. Celebrants, also called officiants, often perform ceremonies in parks, on beaches, on mountains, on boats, on hiking trails, in hotels, in banquet halls, in private homes, and many other places. Laws in each state of the United States vary about who has the ability to perform wedding ceremonies, but celebrants or officiants are usually categorized as "clergy" and have the same rights and responsibilities as ordained clergy. There is some controversy over whether these laws promote religious privilege that is incompatible with the United States Constitution. In the United States, celebrants are professional ceremony officiants who believe in the power and effectiveness of ceremony and ritual to serve basic needs of society and the individual. They collaborate with their clients to create and perform personalised ceremonies that reflect the client’s beliefs, philosophy of life, and personality, not the celebrant’s.
In Australia, Celebrants have a slightly different role, as regulated by local and national laws.
By faith
Christianity
Catholicism
In the Catholic Church, it is the bride and groom who perform the Sacrament of Matrimony, but a marriage can only be valid if the Church has a witness at the wedding ceremony whose function is to question the couple to ensure that they have no obstacle to marriage and that they are freely choosing to wed each other. All ordained clergy may witness the wedding ceremony itself, though usually the wedding ceremony occurs during a Mass, which deacons lack the authority or ability to celebrate; however, in weddings that take place inside Mass, the deacon may still serve as the witness to the wedding, provided that a priest or bishop celebrates the Mass; and in weddings that take place outside Mass, the ceremony is the same for deacons, priests, and bishops.
In Judaism, a Rabbi officiates Jewish weddings. However, the Rabbi's function is to ensure that the Jewish religious laws of the wedding ceremony are followed, particularly making sure that the Jewish witnesses are valid. The Rabbi traditionally recites the blessing for the ceremony on behalf of the groom, although in ancient times the groom would have recited this blessing.
Non-religious
Non-denominational
Some organizations have limited or no requirements for ordination, like American Marriage Ministries and the Universal Life Church. Such organizations may be known as ordination mills, however in most cases, their ordinations provide the same legal standing as mainstream officiants, and marriage licenses signed such organizations are valid and recognized. Many non-religious people have their weddings in non-denominational churches, mosques, and synagogues.
Humanist
A number of humanist organizations provide credentials to individuals who may solemnize marriages in whatever manner they choose; these are known as Humanist celebrants.
