"We thank you ... for assuring us in these holy mysteries that we are living members of the Body of your Son, and heirs of your eternal kingdom" (Book of Common Prayer, p. 366).
It goes by several names: Holy Communion, the Eucharist (which literally means "thanksgiving"), mass. But whatever it’s called, this is the family meal for Christians and a foretaste of the heavenly banquet. As such, all persons who have been baptized, and are therefore part of the extended family that is the Church, are welcome to receive the bread and wine, and be in communion with God and each other.
The Holy Eucharist can be found on pp. 316-399 of the Book of Common Prayer.