“Sacraments are ‘powers that come 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,” (CCC, no 1116). Colloquially, sacraments are visible signs of invisible grace.
Jesus gave us the Sacraments to call us to worship God, to build up the Church, to deepen our faith, to show us how to pray, to connect us with the living Tradition of the Church, and to sanctify us. While God works primarily through the Sacraments, He also touches us through the community of the Church, through the lives of holy people, prayer, spirituality, and acts of love. But "for believers, the sacraments of the New Covenant are necessary for salvation... the fruit of the sacramental life is that the Spirit of adoption makes the faithful partakers in the divine nature by uniting them in a living union with the only Son, the Savior," (CCC, no.1129).
There are seven sacraments instituted by Christ that the Church upholds as vital to the Christian life: Baptism, Reconciliation, Eucharist, Confirmation, Marriage, Anointing of the Sick (including Last Rites), and Holy Orders (priesthood).
Please see below for more information on sacramental preparation and formation.