In Genesis 1:26, God (elohim) speaks to another person who is not himself, saying “Let us…” or “Let’s”. If I say to my friend, “Let us go to the Mall,” I am not saying that the person I am speaking to is another person of myself.
El is the Hebrew name for God. Elohim is the plural form. The name itself indicates a plurality within God.
The word “elohim” can mean either plural “gods” or singular “god” The point trying to be made here is that there is nothing in the word elohim that means a “plurality of individuals,” anymore than its use of Moses in Exodus 7:1. God said to Moses: “See, I have made thee a god [ELOHIM] to Pharaoh.” No one would say Moses is a plurality of individuals. There is nothing in that word that identifies a “plurality of individuals.”
We should also note that elohim in the plural means “gods” — not persons. Thus the argument that its plural usage means a Trinity would tend to mean that there are three gods, not three persons in one God, as is claimed for the Trinity doctrine.
The creed of the Jews and what Jesus also confirmed is, “Hear, O Israel; The Lord our God, the Lord is one.” Not three.