Magic Academies are the only organisations and institutions that regularly teach individuals to use magic abilities. The majority of them is focussed on using these magic abilities for Combat purposes, there are currently none left that teach only non-combat applications of magic. This is due to Magic Power being a massive force in Military. Therefore, any state sees magic users as an immensely valuable asset or potential danger, doubly so since magic users not taught proper use of their abilities may accidentally cause large scale damage.
This obviously only counts for Innate Magic Users, since all other kinds of magic have to be acquired. Most Magic Academies also serve as institutions to acquire some or all of the other branches of Magic ( Geomancy, Necromancy, Shamanism, Alchemy, Demonolatry ).
Magic Academies on the main continent traditionally follow a system of secrecy to protect their practitioners and pupils, as well as to more easily travel through the world. The remaining Magic Academies are now all of the nomadic kind, there are no stationary ones left (Stationary Magic Academies however, where always the minority). As such they usually also function as Mercenary Companies, although various Academies allied themselves with definite States or Organisations in the past.
This system of secrecy makes them camouflage as other, unobtrusive organisations of some kind or other, usually travelling ones.
Continental Librarian Association