Is it OK to bury a Muslim in a coffin?

Question: In some non-Muslim countries, the corpse is placed in a coffin and then buried in the grave. What is our duty in such a situation?

Answer: There is no problem in placing the corpse in a coffin when burying him in the ground. However, the religious requirements of burial must be fulfilled; and one of those requirements is that the corpse be placed on its right side with the face towards the Qiblah.

Ayatollah Al-Sayyid Ali Al-Husseini Al-Sistani