The Mass consists of two great parts that together constitute one single act of worship: the Liturgy of the Word, with Scripture readings, the homily, the Creed, and general intercession; and the Liturgy of the Eucharist, with the presentation of the bread and wine, the Eucharistic prayer in which Christ's Body and Blood become present, and the Communion Rite.
The Liturgy also has rites as the start of Mass that prepare us for God's Word and the Eucharist and rites at the end of Mass that send us forth into the world. In the Introductory Rites, we gather together to prepare our souls to encounter God in His Word and Jesus in the Eucharist, while in the Concluding Rites, the faithful are sent forth to bring the good news of salvation to the entire world.
Catholics are obliged to attend Mass on Sundays and Holy Days of Obligation and to receive the Eucharist at least once a year, if possible during the Easter season.