You need to understand, that you have to follow specific format, in order to write a good application letter.
Yes, you have to say things in a short and precise manner, since an application letter comes under the category of Formal Letter
I am writing the following letter to the Principal requesting him/her to issue school leaving certificate of my daughter
Hope, it helps every single one of you.
City Montessori School,
Subject (Request to issue school leaving certificate of my daughter)
I am X (Your name), guardian of Arpita Sharma , who is now an ex student of your school (Class 10th passed) requests you to kindly issue school leaving certificate of my daughter, as we are shifting to a new location and joining a new school in its vicinity
Kindly issue at the earliest as the date to submit Transfer Certificate is nearing and we need to submit it as soon as possible, in order to avoid any last minutes problem.
I will be highly obliged,
Class 10th Student