The Book of Common Prayer describes Confirmation this way:
“The Anglican Church requires a public and personal profession of the Faith from every adult believer in Jesus Christ. Confirmation or Reception by a Bishop is its liturgical expression. Confirmation is clearly grounded in Scripture: the Apostles prayed for, and laid their hands on those who had already been baptized
(2 Timothy 1:6-7; Acts 8:14-17; 19:6).
In Confirmation, through the Bishop’s laying on of hands and prayer for daily increase in the Holy Spirit, God strengthens the believer for Christian life in the service of Christ and his kingdom. Grace is God’s gift, and we pray that he will pour out his Holy Spirit on those who have already been made his children by adoption and grace in Baptism.”
Confirmation has been practiced by the Church since its beginning in the book of Acts in the Holy Scriptures.