The visible reality we see in the Sacraments is their outward expression, the form they take, and the way in which they are administered and received. The invisible reality we cannot “see” is God’s grace, his gracious initiative in redeeming us through the death and Resurrection of his Son. His initiative is called because it is the free and loving gift by which he offers people a share in his life, and shows us his favor and will for our salvation. Our response to the grace of God’s initiative is itself a grace or gift from God by which we can imitate Christ in our daily lives.
The saving words and deeds of Jesus Christ are the foundation of what he would communicate in the Sacraments through the ministers of the Church. Guided by the Holy Spirit, the Church recognizes the existence of Seven Sacraments instituted by the Lord. They are the Sacraments of Initiation: Baptism, Eucharist and Confirmation; the Sacraments of Healing: Penance and Anointing of the Sick (performed only by a priest), and the Sacraments of Communion: Marriage and Holy Orders. Through the Sacraments, God shares his holiness with us so that we, in turn, can make the world holier.
Reference: Sacraments and Sacramentals, United States Conference of Catholic Bishops. Retrieved from http://www.usccb.org/prayer-and-worship/sacraments-and-sacramentals/