Baptism is the first of the seven sacraments, and the “door” which gives access to the other sacraments. Baptism is the first and chief sacrament of forgiveness of sins because it unites us with Christ, who died for our sins and rose for our justification.
Baptism, Confirmation, and Eucharist constitute the “sacraments of initiation” by which a believer receives the remission of original and personal sin, begins a new life in Christ and the Holy Spirit, and is incorporated into the Church, the Body of Christ.
The rite of Baptism consists in immersing the candidate in water, or pouring water on the head, while pronouncing the invocation of the Most Holy Trinity: the Father, the Son, and the Holy Spirit.