The headmaster is the top administrator and head teacher at a school, and fulfils the duties associated with what is more often called a principal in the United States. The term is most common at private schools and overseas, though the Boston Public Schools system also uses it. The headmaster generally has final say in matters of hiring, firing and discipline. Respect the headmaster's authority and formally address an envelope before you send a letter to him.
Write "Headmaster," followed by the headmaster's full name. If the headmaster's name is Wackford Squeers you would write, "Headmaster Wackford Squeers." If you do not know the headmaster's first name, omit it.
Write the full name of the school on the second line.
Write the street address of the school on the third line.
Write the city, state abbreviation, and the zip code on the final line. Separate the city and state abbreviation with a comma.
Be sure to spell all names and locations (such as the name of the headmaster and school) correctly.