The Eucharist and the sacraments are the essential elements
in the life of the Catholic Church.

The seven sacraments in the Church are:
Baptism, Penance, Eucharist, Confirmation, Matrimony, Holy Orders
and Anointing of the Sick.

Sacraments are "powers that comes forth" from the Body of Christ, which is ever-living and life-giving. They are actions of the Holy Spirit at work in his Body, the Church. They are "the masterworks of God" in the new and everlasting covenant. 
Catechism of the Catholic Church 1113 & 1116