Begin the holy confirmation letter by writing the word "Dear," followed by the recipient's name. The first paragraph should remind the recipient that her spiritual journey has not ended simply because she is now confirmed, nor should the recipient, if young, now consider herself an adult within the church.
Use the next paragraph to detail the recipient's spiritual accomplishments. Specifically, mention her receiving the Sacraments of Initiation, her Baptism and her Confirmation. Mention that she is now a member within the Body of Christ and that the confirmation is a fulfillment of a spiritual promise she made when she was first baptized.
Next, mention that while her formal religious instruction is now complete, you hope she continues to learn about the millennia of Christian history and that this ongoing education brings her closer in relationship to God.
Remind her to keep her dignity during this ongoing journey and, optionally, integrate stories of your own confirmation. This includes how and what you felt at the time and how feeling accepted into this spiritual community has brought ongoing comfort in times of trouble.
Encourage her to embrace God in times of despair and to understand that she cannot always understand God's will. End the confirmation letter with "Love," followed by the sender's name.