Date: dd / mm / yy
The Principal, 
School Name...

Subject: Application for setting up a canteen in the school campus

Respected Sir,
I, on behalf of the students of class (give your class and section) of you school, have to honor to state that (school name) is one of the most famous schools in the district (name). But it is just matter of great regret that there is no canteen  in you school campus. We acutely desire of a canteen. Our classes start at 9:00 a.m. and break up at 4:00 p.m. There is a thirty minute break at lunch time. However, most of the learners cannot go home for lunch given that they live far away. They have to take their lunch on roadside hotels. But many of these are unhygienic and bad for our health. Moreover, the school canteen may provide low-priced hygienically prepared foods.
Inside the light of the preceding circumstances, we would fervently request you to build a canteen in the institution campus and oblige you thereby.
Sincerely yours,
Student name....
On behalf of the students of class.....