The assembly-accredited professor of unreserved belief in The Christ is to be inducted into The Company of The Committed Ones by means of the ritual of water immersion in the Name of (= by the delegated authority of) The Father, and of the Son, and of the Holy Ghost.
As the Risen Jesus affirmed and applied in His command to His Disciple/Apostles in Mt. 20:19, the Name is, and must be, singular in the Greek, as it is applied to the unified personification of the term Authority; that is, a title encompassing all three of the Trinity.
In the English, that term is singular and capitalized as being the state of a proper noun, and accorded the definite article, not being "a god"; but rather being "The God" above whom there is no higher honor, or power of administration or force, or authority.
In the New Testament Greek, that is "το θεός" (John 1:1 TR), which is distinguished in honor by using the definite article.
But in the Hebrew, the Name of the Trinity appears first in Genesis 1:1 as אלהים, a uniplural noun sounded as "Elohim" and translated as "God". In Cnapter 3 it is amplified buy adding the honorific "Jehovah," thus making His Name יהוה אלהים, sounded as Jehovah Elohim, and translated into the highest honoring form of English as "the LORD God" Who is the entity preceding all other, and the Creator of all that is in the temporal natural dimension.
So it is the One Title, Jehovah Elohim, The LORD God, comprises all Three Manifestations of The Godhead, of which the Risen יהוה (Jehovah = LORD), Kύριος Ἰησοῦς (Kurios Yesous), Lord Jesus has the executive role of Jehovah Elohim, LORD God.
Selah.
And, in English, we find...
... let US make man in OUR image.