write an application to your principal that you are suffering from viral fever that's why you want 4 days leave ?

To

The Principal
ABC School
Address:-
SUBJECT : Application for sick leave

Respected Sir,

         I beg to say that I am a student of class VI. I am suffering from fever since last night and my doctor has advised me to take rest for four days. So I shall not be able to attend the school.
kindly grant me leave for xx-xx-2018 to xx-xx-2018. I shall be very grateful  to you.

Yours obediently

Name-
Class-
Date-