Answer:
1. They fixed the roof.
Passive: The roof was fixed by them.
2. The burglars made a huge hole in the steel door.
Passive: A huge hole was made by the burglars in the steel door.
3. The organizers arrange the art exhibition every year.
Passive: The art exhibition is arragned by the organizers every year.
4. Joseph rings the church bells regularly.
Passive: The church bells are rung by Joseph regularly.
5. She helps her mother in household chores.
Passive: Her mother is helped by her in householde chores.
6. A man requested the stranger to leave the meeting.
Passive: The stranger was requested by a man to leave the house.