Sacrament of Baptism
Baptism is the sacrament of admission to the faith, bringing sanctifying grace to the person being baptized. The baptism of infants is the most common form but unbaptized children or adults who wish to join the faith must also receive the sacrament. A person is to be baptized only once in their life and the Catholic Church recognizes baptisms done by most other Christian denominations as valid. In the rite of baptism holy water is usually sprinkled or poured on the head by a priest who simultaneously invokes the Trinity with the words, “I baptize you in the name of the Father and of the Son and of the Holy Spirit.” The old self is said to die in the waters and a new self emerges, mirroring the death and resurrection of Christ.
How it's administered
Baptism is performed with water and the Trinitarian invocation, "I baptize you: In the name of the Father and of the Son and of the Holy Spirit". The Christian churches' forms and rituals vary but the candidate may be wholly or partly immersed in water, water may be poured (affusion) over the head or a few drops may be sprinkled or placed (aspersion) on the head. Most of those baptized in the early church were adult converts. By the second century, infant baptism was a common practice and remained the accepted method in the Eastern and Western churches.