"The Catholic Church offers to all people the possibility of encountering the living God today and finding in him lasting meaning and hope." https://www.usccb.org/beliefs-and-teachings
Why become Catholic?
"Prior to beginning the process of becoming a Christian, an individual comes to some knowledge of Jesus Christ, considers his or her relationship with Jesus Christ and is usually attracted in some way to the Catholic Church. For some, this process involves a long period of searching; for others, a shorter time.
Often, contact with people of faith and a personal faith experience lead people to inquire about the Catholic Church. After a conversation with a priest or a parish director of Christian Initiation, the person, known as an "inquirer," may seek acceptance into the Order of Catechumens, through the Rite of Acceptance. During this Rite, the inquirer stands amidst the parish community and states that he or she wants to become a baptized member of the Catholic Church. The parish assembly affirms this desire and the inquirer becomes a Catechumen."
For Baptized Non-Catholic Christians
"Coming into full communion with the Catholic Church describes the process for entrance into the Catholic Church for already baptized Christians. In most cases, these individuals make a profession of faith but are not baptized again. To prepare for this reception, Candidates usually participate in a formation program to help them understand and experience the teachings and practices of the Catholic Church. The Candidates may be received into the Catholic Church at the Easter Vigil or at another Sunday during the year depending on pastoral circumstances and readiness of the Candidate."