Question

Letter to a principal complaining about misbehavior of teacher with student

Answer 1

The format will have:
#senders address
#date
#addresses (receivers) address
#subject (letter of complaint against teachers behavior in school towards the students)
#A respective Salutation to the principal
#Basic Introduction
#Body
#Conclusion
#The last Salutation
#Your name and Signature(order of these two can change)

The Basic introduction should have / should say a little about what you are about to say and why are you conveying this now.

The body should have the explanation of what happened, how do you think the teacher's behaviour is wrong, how many days were we suffering or seeing this, other information. It's based on our imagination.

The conclusion should be a request to the principal to take strict action (you can also gain points by showcasing the duty a teacher have, contradicting it with the actions of the teacher in the letter, you can include it in the body my be)

Then end the letter in manner that your one choice to solve the problem is this.

You can either be another teacher or student from the class the teacher is taking as you wish, if not said in the Question

I think this will help you even a little:)