Catechism of the Catholic Church §1630 — excerpt
The priest (or deacon) who assists at the celebration of a marriage receives the consent of the spouses in the name of the Church and gives the blessing of the Church.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.