The Anunnaki is a name given to all the Sumerian gods
The Sumerians considered that God was responsible for matters related to natural and social orders.
That the universe arose through a series of creation myths. First, Namu, the primordial waters, gave birth to Anu (sky) and Ki (earth), who mated and produced a son named Enlil. Enlil separated the sky from the earth, because the air expands. They believed that the sky and the earth were connected, and then Enlil claimed that the earth was his own.
It is believed that Enki, the son of Anu and Ki, was the one who created humans. Heaven was reserved exclusively for the gods, and upon their death, it was believed that all human souls, regardless of their behavior while alive, would go to Erkala, a cold, dark cave deep underground, ruled by the gods Ereshkigal. The only food available was dry dust. Ereshkigal was later believed to have ruled alongside her husband Nergal, the god of death.
Among the most important Sumerian gods: Anu, the god of heaven, Enlil, the god of wind and storm, Enki, the god of water and human culture, Ninhursag, the goddess of fertility and earth, Utu, the god of the sun and justice, and his father, Sin, the god of the moon. During the period of the Akkadian Empire and beyond, Inanna, the goddess of sex, beauty, and war, was widely worshiped by the Sumerian people and appears in many myths, Including the story of her descent into the underworld.
Sumerian religion strongly influenced Mesopotamian religion; Elements of it were preserved in the myths and religions of the Akkadian Empire, Babylonia, Assyria, and other cultural groups in the Middle East. Mythologists have noted many similarities between the stories of the ancient Sumerians and those later recorded in the early parts of the Hebrew Bible, especially in the most important book, Genesis.
Source: websites