Confirmation and chrismation
Confirmation strengthens baptismal grace and the gift of the Holy Spirit for Christian witness. Eastern Catholic traditions commonly call it Chrismation and celebrate it with Baptism, including for infants. Latin practices concerning age and sequence differ. It is not simply a graduation ceremony or an assertion that a young person no longer needs formation.
Follow the sources
An original library introduction, with sources for further study. This is a starting point rather than a complete treatment or a finished formation lesson.