The formula in the Roman Catholic Church is:
Ego te absolvo a peccatis tuis in nomine Patris et Filii et Spiritus Sancti. Amen. Ordo Paenitentiae, n. 46

I absolve you of your sins in the name of the Father and of the Son and of the Holy Ghost. Amen.
Most theologians agree that in order for the absolution to be valid, i.e. effective in the eyes of the Church, three elements must be present:
  • the one absolving (ego)
  • the one absolved (te)
  • what’s absolved (a peccatis)