Christianity is a religion based on the basic premises relating to Jesus of Nazareth who is considered the Son of God. Catholicism is one of the several denominations of the main Christian faith and has the largest followers among all the Christian sub-faiths of Lutheranism, Protestantism etc.
Catholics believe in the seven sacraments (holy moments) but other Christian denominations do not recognize all the sacraments. The seven Sacraments for Catholics are Baptism, Eucharist, Confirmation, Marriage, Ordination, Reconciliation/Confession and Anointing of the Sick.
Catholics also assert that Saint Mary, Mother of Jesus was the greatest saint and did not sin but other Christians like Protestants do respect Mary as Jesus’ mother but believe that she sinned like anyone else. While Catholics believe Mary’s resurrected body went to heaven immediately, other Christians believe that the body was buried.
Also, Catholics, unlike other Christians, believe in a spiritual leader of the Roman Catholic Church. He is known as the Pope and regarded as the direct descendant of Saint Peter the Apostle. Catholics believe that Jesus had asked St Peter to build the Basilica in Rome. You are necessarily a Christian if you are a Catholic but you may not be a Catholic if you are a Christian as you may believe in a different Christian denomination.
Unlike other Christians, Catholics also believe in a spiritual and literal interpretation of the Bible. Catholics also believe in typology which accepts events in the Old Testament as allegories for events that follow in the New Testament. Catholics, unlike other Christians, are more strict about following the Scriptures word for word and are not very open to interpretations unless given by bishops. Moreover, Catholics believe that the end of the world as given in the Book of Revelations is not a metaphoric description but will actually take place in the future. Roman Catholics also believe in the process of confessions to a priest while other Christians believe in an inner dialogue with Jesus.
However, all Catholics, like other Christians believe that Jesus is the savior of humanity and he died on the cross to atone for the sins of all humanity. Catholics and all other Christians believe in the Holy Trinity of the son, the Father and the Holy Spirit.
Catholics also believe that Man retained some goodness even after the Fall in the Garden of Eden but most of other Christian sub-faiths teach that Man fell into complete depravity after the Fall.