by sex, money or writing, the girl who is just all grown up is transferred.
only the freed slave girl is free.
and her work is hers.
Marriage is done by sex, money or written document. a young woman, a na'arah, leaves her father's house to go to her husband. The produce from her work belongs to her father and then to her husband. in contrast the freed slave girl when she becomes a na'arah just leaves.