Question

sick leave application

Answer 1

respected (the addressee),
respected mam\sir I kindly request you to grant me leave (date ) as I am suffering from ( reason) .I request you to oblige the same.
yours faithfully,
(name)

Answer 2

To
the principle
school name.......
through the class teacher 
subject-I am suffering from fever 
respcted sir 
          i am mostly humbly to say you that i am not able to attend my class