Confirmation is a tradition that has been common in many denomations for a long time. Students typically around the time of middle school go through a process of instruction about the core teachings of Christianity and some of the doctrines that make their denomination unique. The confirmation process primarily happens in denominations that practice infant baptism; at the end of their instruction process (maybe 1-3 years), the students make some sort of declaration of their faith and their desire to own their faith.
Confirmation is not something mandated by scriptures. Despite not being written about in the scriptures, the idea of instructing students on important theological issues is certainly a scriptural practice. In fact confirmation is a form of youth ministry that has been happening in many main line denominations even before modern youth ministry was prevalent. Because scriptures don't require confirmation, there are also several different ways that a church might go about doing confirmation.
Five Ways to Do Confirmation
Pastor-Led Model. This is the most traditional model. Confirmation is led by the senior leader of the congregation. The pastor spends classroom time instructing the students on the catechism. The pastor-led model places a high importance on the pastor being the main teacher and often involves extensive instruction times and a lot of memorization.
School Model. The school model is popular in congregations that also have a day school. In this model of confirmation, instruction takes place during a religion class and is done just like any other class as a part of the school day. Students have homework, tests to study for, and parts of the catechism to memorize.
Youth Group Program Model. The youth group model is the model of confirmation that makes confirmation look a lot like a typical youth ministry program. It runs a youth ministry program centered around the confirmation process that targets the age of the students with games, videos, and fun activities and pairs that with the key doctrines that need to be taught. The youth group model often will also incorporate discussion paired with the main teachers lesson. In this model the importance of memorization and the transfer of information is often lesser than the previous two models.
Small Group Model. The small group model is a model of confirmation that focuses on instruction of students within a small group of 6 to 10 students. Certainly some confirmation classes may only have this many students, but this model focuses on being led by an adult volunteer or youth leader whose primary job is to build relationships with the students and to have weekly bible studies centered around the lessons required. The small group model tends to be more about the conversations around the topics than a teacher telling students what to they need to know. That being said, there is no problem for small gorups to have a clear lesson plan of what needs to be covered over the course of a year.
Family Based Model*. The family based model is the model of confirmation that focuses on having parents as the primary teachers of confirmation. The church organizes and equips the families by giving them the tools and resources needed so that they can spend time teaching and discussing theology with their families. While the other models focus primarily on the church's role in confirmation, this model focuses on the parental role in confirmation. Coupled with a healthy student ministry, the family based model can be a great tool in equipping families to disciple their children.
*Because of our family based confirmation I am a bit biased in my opinion on confirmation.