Since you wanted to submit the letter to you local government, it is highly subjective that what is the specific requirement of that agency. You can contact administration of that agency for the required format. More importantly, if you wanted to draw the attention of the officials on a particular matter which you think the agency has missed, attach as many supporting fact and data as reference you can find which directly relates to your concern. At the time of submission, do not forget to get a written acknowledgement over the submitted letter/application, which will help in future re-investigation on the progress over your application.