The Sacrament of Baptism is one of the 3 Sacraments of Initiation.
Baptism, or in Greek - baptizein, means to plunge or to immerse. It is the only Sacrament which is found common across all the Christian denominations and is also known as the sacrament of faith because it initiates the person into the faith.
The Sacrament of Baptism washes away original sin and gives us a new life in Christ. It leaves an indelible spiritual mark which cannot be erased and repeated. After receiving this Sacrament, one's faith must grow and be nurtured in a community.
The graces (supernatural gifts) of Baptism are: 1) All sins are forgiven, 2) we experience new birth in the Holy Spirit and 3) we become adopted children of God.
Lay people can only perform baptisms in cases of near deaths.
The matter (visible sign) is water.
The form (words) are "I baptise you in the name of the Father, and of the Son, and of the Holy Spirit."