How To Write A Medical Permission Letter . Customizable child medical consent templates. How do i write a letter to provide medical permission? 30 Great Authorization Letter Templates (Medical, Travel etc.) from templatearchive.com Therefore, i am writing this letter to state that i authorize _____(name of the doctor) for the medical treatment decisions on the provided date _____(mention date). For example, times new roman or arial 12 point works best. State the objective of this authorization letter in very clear words.