bai, happy new year! i'll try to answer the query, well actually not me personally..hehehe
but from this link:
The Forgiveness of Sins | Catholic Answers
All pardon for sins ultimately comes from Christ’s finished work on Calvary, but how is this pardon received by individuals? Did Christ leave us any means within the Church to take away sin? The Bible says he gave us two means.
Baptism was given to take away the sin inherited from Adam (original sin) and any sins we personally committed before baptism—sins we personally commit are called actual sins, because they come from our own acts. Thus on the day of Pentecost, Peter told the crowds, "Repent, and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins; and you shall receive the gift of the Holy Spirit" (Acts 2:3

, and when Paul was baptized he was told, "And now why do you wait? Rise and be baptized, and wash away your sins, calling on his name" (Acts 22:16). And so Peter later wrote, "Baptism . . . now saves you, not as a removal of dirt from the body but as an appeal to God for a clear conscience, through the resurrection of Jesus Christ" (1 Pet. 3:21).
For sins committed after baptism, a different sacrament is needed. It has been called penance, confession, and reconciliation, each word emphasizing one of its.aspects. During his life, Christ forgave sins, as in the case of the woman caught in adultery (John 8:1–11) and the woman who anointed his feet (Luke 7:4

. He exercised this power in his human capacity as the Messiah or Son of man, telling us, "the Son of man has authority on earth to forgive sins" (Matt. 9:6), which is why the Gospel writer himself explains that God "had given such authority to men" (Matt. 9:

.
Since he would not always be with the Church visibly, Christ gave this power to other men so the Church, which is the continuation of his presence throughout time (Matt. 28:20), would be able to offer forgiveness to future generations. He gave his power to the apostles, and it was a power that could be passed on to their successors and agents, since the apostles wouldn’t always be on earth either, but people would still be sinning.
God had sent Jesus to forgive sins, but after his resurrection Jesus told the apostles, "‘As the Father has sent me, even so I send you.’ And when he had said this, he breathed on them, and said to them, ‘Receive the Holy Spirit. If you forgive the sins of any, they are forgiven; if you retain the sins of any, they are retained’" (John 20:21–23). (This is one of only two times we are told that God breathed on man, the other being in Genesis 2:7, when he made man a living soul. It emphasizes how important the establishment of the sacrament of penance was.)
personally, though the bible,sacraments,ancient church traditions offer ways how sins can be forgiven
there are no absolutes about forgiveness of Sins, by faith i believe Christ alone Can forgive our sins in His own way
may it be through baptism,confession, divine intervention,personal conviction...etc
as a Catholic, going to a priest for confession, with the apostolic succession and most of all by faith..
i believe the sacrament of confession helps remove the guilt feelings caused by sins
and it offers a very nice feeling of hope for a brand new start.
All glory to Christ Jesus.