According to Genesis, the patriarch Noah built Noah's Ark. Genesis 6 presents Noah as a righteous man who received God's instructions to construct the vessel before the flood.
The account names Noah's wife, his sons Shem, Ham, and Japheth, and the sons' wives as the human occupants who entered the ark. Noah is also responsible for bringing animals aboard and later releasing birds to observe the condition of the land.
Noah is distinct from other major patriarchal figures in Genesis. Abraham appears later in the book, while Moses belongs to the much later biblical book of Exodus. The name Noah is therefore the canonical answer when the question asks who built or commanded the ark in the Genesis narrative, even though flood stories from other cultures feature different heroes.