Dear (Principles name)
I am writing to you today to apologize for my poor behavior at school. I made some very poor choices and you had to take time out of your day to deal with the situation at hand. I understand that you are extremely busy and that you have better things to do than discipline kids who just want to get into trouble. I am very sorry for the poor choices that I made.
In the future I promise to make better choices. I know that getting in trouble disturbs the teachers who don’t have to take the time to deal with me and my decisions. School is for learning and when I ditch school and do bad things, I miss out on important educational opportunities and I am learning to understand that. From now on I will be a better student. I will come to school everyday "Unless Im Sick" and try my best to stay out of trouble. I promise to watch myself better as a person and as a student for school.
Thank you for your time and please accept my apology.
Sincerely,
(Your Name)