Question

Write a letter to request principal open the karate class in school

Answer 1

You probably won’t be able to teach karate through the school. I would suggest a venue such as the YMCA. You will also need to get your clearances to work with kids. And for any proposal you submit to the directors of the Y, or a Rec League, I’d suggest you find someone to edit it for you. You want your letter to reflect you as an expert in your field. A brief bio with your credentials should also be included with a synopsis of what and how you teach.
thanks