Any baptized Catholic who has reached the age determined by the bishop for confirmation is a candidate, (in the US it is anywhere from the age of reason to adulthood) when he has been instructed and prepared for the sacrament. The bishop, or those he delegates, determine what constitutes preparation and readiness. Contact your Catholic parish and simply ask. The preparation includes study of Christian doctrine so that the candidate can make an informed profession of faith, the nature of and effects of the sacrament and other sacraments of initiation and the action of the Holy Spirit. In this diocese preparation is 2 years for teens, one year for adults and a retreat focusing on those elements is part of the immediate preparation.
If you are asking about the rite of Confirmation, it entails presentation of the candidates to the bishop by the pastor, the sponsor’s affirmation that the candidate is ready, profession of faith, laying on of hands and the prayer over the candidates invoking the Holy Spirit, and anointing each candidate with chrism (holy oil blessed by the bishop for this purpose). This is in the context of Mass.
