The very first words recorded in the Bible are "In the beginning God created the heavens and the earth."
The Hebrew words for "God created" are "Elohem bara". El means God, such as in El Shaddai, which means God almighty, or Bethel which means “house of God”, or Michael which means "who is like God".
El is God in the singular tense. Elohim means God in the plural tense, or more than one, such as when "s" is added onto a word in the English language. The word bara means created and is in the singular tense. The root word of bara is bar, like in bar mitzvah. Bar means son. So, in Hebrew the root word of created is son. We might say that is because the son did the creating.
The next verse that is written in God's holy word says that the Spirit of God, Roo-ach Elohim, was hovering over the face of the waters. Right here, in the first two verses of the bible, three aspects of God are mentioned having an active part in the creation of the world. We have Elohim commanding, the Son creating and the Spirit moving.
That is why in that first chapter of the Bible, in verse 26, God was able to say "Let US make man in OUR image, according to OUR likeness". There are three plural possessive pronouns in that one verse. Did you catch them? Let US, that's one, make man in OUR image, that's two, after OUR likeness, that's three. Three times the plural words OUR or US are used in describing God in a plural way. This is because God is one in the same way a family can have 3 individuals in it yet still be one family.
The family of God is comprised of God Almighty, His Son the Messiah, and the Holy Spirit; these 3 make one family.