Write an application to the Principal of your school apologizing for being absent from the school without an application for leave. Your name has been struck off the rolls, request the Principal to readmit you.

To
The Principal,
XYZ Public School,
ABC City 

October 17, 20xx 

Respected Sir, 

With due regard, I want to state that I am a student of class IX-A of your school. I beg to apologize for being absent from school for ten days without an application for leave. Actually, I was down with malaria and was admitted to a hospital. My mother is illiterate and my father is in the army. No student of my locality reads in the school. Therefore, I could not send my application. Yesterday, I received a letter from you that my name has been struck off the rolls. Sir, I am still not in a position to come to school as the doctors have advised me complete rest for the next five days. I am sending my application and medical certificate through my mother. Keeping in view the circumstances kindly re-admit me and also give me leave for five days.

I shall be highly grateful to you.

Yours obediently,
Rajesh Kumar
Class IX-B, Roll No. 11