According to the Catechism of the Church in number 830 it is established that, the word "catholic" means "universal" in the sense of "according to the totality" or "in keeping with the whole". The Church is Catholic, then, in a double sense:
First, the Church is catholic because Christ is present in her. "Where there is Christ Jesus, there is the Catholic Church." In her subsists the fullness of the Body of Christ united to his Head "And he put all things beneath his feet and gave him as head over all things to the church, which is his body, the fullness of the one who fills all things in every way." (Eph 1, 22-23).
Secondly, the Church is catholic because she has been sent out by Christ on a mission to the whole of the human race: “Go, therefore, and make disciples of all nations, baptizing them in the name of the Father, and of the Son, and of the holy Spirit" (Mt 28:19). Note that this is a universal invitation, it is for everyone.
Being Catholic then means that Christ is present in you and has sent you to be his witness in your own family and in the world. All men are called to belong to the new People of God.