Of all seven sacraments, the Holy Eucharist, or Holy Communion, is the most central and important to Catholicism. Holy Communion is offered at every Mass, and in fact, the ritual of the Mass is largely taken up with preparing the hosts and wine to become the body and blood of Christ and the congregation to receive the body of Christ. Transubstantiation is the act of changing the substances of bread and wine into the substances of the Body and Blood of Christ.

1324 The Eucharist is the "source and summit of the Christian life." "The other sacraments, and indeed all ecliastical ministries and works of the apostolate, are bound up with the Eucharist and are oriented towards it. For in the blessed Eucharist is contained the whole spiritual good of the Church, namely Christ himself, our Pasch" Catechism of the Catholic Church

Of all seven sacraments, the Holy Eucharist, or Holy Communion, is the most central and important to Catholicism. Holy Communion is offered at every Mass, and in fact, the ritual of the Mass is largely taken up with preparing the hosts and wine to become the body and blood of Christ and the congregation to receive the body of Christ. Transubstantiation is the act of changing the substances of bread and wine into the substances of the Body and Blood of Christ.

• Latin (Western) Rite: Holy Communion is in the form of consecrated unleavened hosts made from wheat flour and water, just like the unleavened bread used by Jesus at the Last Supper. The host is flat and the size of a quarter or half-dollar. Latin Catholics may receive the host on their tongue or in their hand if the local bishop and the national conference of bishop’s permit.

• Byzantine (Eastern) Rite: Catholics receive consecrated leavened bread (the yeast or leaven symbolizes the Resurrection), which is placed inside the chalice (cup) of consecrated wine. The priest takes a spoon and gingerly places a cut cube of consecrated bread soaked in the consecrated wine inside the mouths of the communicants without ever touching their lips or tongue.

As Catholics, we know that the Holy Eucharist is the source and summit of our faith: it is the Body, Blood, Soul, and Divinity of Our Lord and Savior Jesus Christ. Pope Francis has called it the "Sacrament of Love".

"The Eucharist is at the heart of 'Christian initiation', together with Baptism and Confirmation, and it constitutes the source of the Church’s life itself. From this Sacrament of love, in fact, flows every authentic journey of faith, of communion, and of witness."

Reception of 1^st communion for Adults is one of the Sacraments of Initiation, called RCIA (Rite of Christian Initiation of Adults), along with baptism and confirmation during the Easter Vigil.

Reception of 1^st communion for children is usually in May (although it can be at other times of the year) and after preparation through catechetical instruction.