Whenever a Muslim has passed away
"Dear Islamic brothers! Whenever a Muslim has passed away, do write بِسۡمِ اللّٰهِ الرَّحۡـمٰنِ الرَّحِيۡم and other holy words on his forehead etc. A slight attention of yours can result in forgiveness for the deceased. (Faizan-e-Sunnat, Blessings of Sunnah,VOLUME 1) "