A formal letter to a school principal / headmaster is usually a letter written by a student, the school's student body, a parents' group, or a parent. One would generally reserve the more important matter / request for the principal / headmaster. For everyday matters relating to school (such as leave application, class allocation, etc.), one would generally write to the relevant teacher in charge instead. Please see the section relating to “Request / Notification to School”.
The purpose of writing to the principal / headmaster depends on your circumstances. This is usually a request letter on more important matters:
(i) request that require the approval of the principal / headmaster;
(ii) complaints against certain school policies, teachers or students at the school; or
(iii) report a serious issue / problem at the school.
For example, complaints about bullying, or prohibition for students to wear masks at school in the face of a pandemic.
It would be helpful to include the student name, class name and the class number, as well as the purpose of the letter in the subject line.
The tone of the letter is set in the introductory paragraph which should be formal and polite. You should keep a pleasant, approachable tone in the letter, even when you are filing a complaint.
How you begin the letter would depend on your relationship with the principal / headmaster, if the principal / headmaster does not know you, introduce yourself / your child and indicate the class name and class number. If the principal / headmaster knows you, you can write a greeting instead and then head straight for the purpose.
It is important to set out the purpose of the letter in the introductory paragraph - for example, I write to you concerning a request, complaint, arrange an appointment for a meeting, etc. It is also good to be tactful and gain some rapport with the principal / headmaster early by expressing your support for the school. Tell the principal / headmaster what you like about this school, and / or praise him / her.
Explain your request or complaint in more detail. You should be clear, direct and focus on the point on what you are requesting or notifying the principal / headmaster about. Always be extremely polite and tactful, no matter how frustrated you are. Don't use abbreviations and slang.
If you are reporting a problem to or notifying the principal / headmaster about a certain issue, be honest and accurate when describing an incident at school (Including the date, time and location). Any facts provided in your letter should be accurate. Do not exaggerate on what happened or the impact on you or your child.
When you outline your request or recommend specific actions to be taken by the school, you should be courteous and reasonable. Put yourself in the position of the principal / headmaster when you write to ascertain the reasonableness of your request. Give good reasons for your request and phrase them correctly to increase your chance of getting a favourable response from the headmaster / principal.
In the concluding paragraph, you should summarise the purpose of your letter in one to two sentences. End the letter positively and thank the principal / headmaster for taking the time to consider your request / issue. Please also inform him /her that you would look forward to a response to the request / complaint / issue raised in the letter.