It's called the "royal we." Monarchs use the plural because when they refer to themselves they are also referring to the state. Archaic today, but remember who commissioned the King James translation.
The plural in this case is literal. “Elohim” is the plural of “Eloah”. The first chapter of the gospel of John expands on its literality, as does Hebrews 7.
Even as recently as Queen Victoria, didn’t she use the royal “we”.
>> It’s called the “royal we.” <<
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Bzzzzzt - Fail!