She was Egyptian. Likely acquired by Abraham during his fearful sojourn in Egypt (Gen 12:16) when Pharaoh gave him "male and female servants." She was a piece of property in a wealthy household.
For ten years, she served Sarai in silence. She had no voice, no choice, and no rights. She was defined entirely by her utility to her masters.
She was formed by servitude. She learned to be invisible. Her identity was "Sarai's maidservant."