Write a letter to your Principal, requesting him for a character certificate and a certificate to the effect that you are a regular student of the school. Also write why you need it.
The Principal
St. Marks School
Delhi
15th March 20XX
Subject: Issue of Character Certificate
Dear Sir
I have been a regular and bonafide student of your school for the past five years. Presently I am in class XI-B and have recently taken my board examinations.
I am writing this letter to you to request you to issue a character certificate to the effect that I have been a regular student of the school.
My father has been posted out of station, so I need this character certificate to seek admission in a new school. We will be leaving next week. So, kindly issue the character certificate before that. I will come and collect it personally from the Administrative Office before I leave.
Thanking you
Yours obediently
Neha Sharma
XI-B