At about the time that Moses was born, a decree had gone out to kill all of the Hebrew male infants in Egypt. To save Moses, his family placed him in a basket and set him adrift in a river. Moses' sister, Miriam, walked along the bank of the river, watching over Moses as he drifted downstream. When the Pharaoh's daughter found Moses, Miriam approached Pharaoh's daughter and offered to help her find a Hebrew nurse to help care for the baby (Moses). The nurse ends up to be Jochebed, Moses' mother.
Years later, Miriam has a victory dance of the Israelite women to celebrate the crossing of the Red Sea (Exodus 15:21). She is called a "prophetess" in Exodus 15:20, which would make her the first woman to be given that title. In Numbers 12, Miriam and Aaron criticize Moses for marrying a Cushite woman, and then further rebel against Moses, claiming that they are equals as prophets. But God confronts them, and strikes Miriam with leprosy for the rebellion. Moses and Aaron both pray for Miriam. She is cured seven days later.
Her name is the Hebrew form of Mary, which became a common name given to Jewish girls, including the Mother of Jesus. Details about Miriam are found in the books of Exodus and Numbers.