The RCIA and associated program educates, then initiates adults to become a Catholic as an adult.
You may be aware that in the past people wanting to become Catholic were required to participate in a program of private instruction with the parish priest, consisting of a set number of weekly ‘lessons’ on Catholic doctrine. After the instructions were completed, the ‘convert’ was baptised (if necessary) and confirmed in a private ceremony with only the priest and a sponsor present.
This changed after the Second Vatican Council in the 1960s. The current process by which new members are brought into the Catholic Church is called the Rite of Christian Initiation of Adults, or the RCIA.