One of the most commonly recited of Catholic prayers in times past, this prayer has fallen into disuse in the last few decades. Prayer for the dead, however, is one of the greatest acts of charity we can perform, to help them during their time in Purgatory, so that they can enter more quickly into the fullness of heaven.
If you are offering the prayer for a particular person, you can substitute "him" or "her" for "them."
Eternal rest grant unto them, O Lord, and let perpetual light shine upon them. May the souls of the faithful departed, through the mercy of God, rest in peace. Amen.