The term Monarchianism means one ruler (mono = one, arche = ruler). This heresy started in the second century by people who claimed to have beeen refuting tritheism by teaching monotheism, the people who held to the monarchaianism position opposed the orthodox Trinitarian doctrine and labeled it as a tritheism. they describe God the Father as the only One ruler with no trinity. They view Jesus as a Created being who is not eternal and is inferior to God the Father, some of them holds to the view of adoptionism that Jesus was adopted into the Family of he GodHead as a lesser god after His Baptism in the Jordan river, they also rejects the Deity of the Holy Spirit.
Mornachianism is divided into two groups, modalist monarchianism and dynamic monarchianism. Modalist monarchianism believe in a trinity of a god who manifests in three modes namely, Father, Son and Holy Spirit. Dynamic monarchianism rejects the whole notion of the trinity and affirms that only God The Father is God ruling in monarchy.
This view is also wrong because it try to repudiate the biblical doctrine of the trinity, though the word trinity is not biblical what the doctrine teaches is absolutely true and biblical, there are no levels of Divinity and Christ cannot be less than God but co-equal and co-existing, it is written in Micah 5:2 that His goingforths are from everlasting, think about the story of redemption, the Father decreed it but it was the Son who made the purchased with His blood and the Holy Sprit sealed that salvation.
Soli Deo Gloria