Q. In which Saff of the Masjid should a child stand for Salaah?
A. Children (non-Baaligh) should stand in the row (saff) behind the row (saff) of the adults. However, if there is one child (non-Baaligh) only, he may stand in the row (saff) of the adults. (Fataawa Mahmoodiyyah 6/489)
Allah Ta’ala Knows Best
Mufti Ismaeel Bassa
themufti.com