Commonly if a student is absent what the students have is send an excuse letter to the teacher, like to whom it may concern, and whatsoever. With that particular letter you should have the inside address, the date of course.
Inside address
date
recipients name
recipients title
recipients address
salutation,
introductory paragraph
reasoning paragraph
hoping for considerations
closing remarks
signature over printed name with date
Inside address
date
recipients name
recipients title
recipients address
salutation,
introductory paragraph
reasoning paragraph
hoping for considerations
closing remarks
signature over printed name with date