Mages
Since the manipulation of mana is an innate human skill, almost all humans in Empyria are "magic-users" by definition. People in all kinds of careers memorize and cast spells to help them do their jobs. Even the least magically-inclined civilians are likely to know one or two spells, for things like boiling water or charging a phone.
People whose jobs heavily involve magic - especially adventurers specializing in magic - are sometimes referred to as wizards, sorcerers, or other titles depending on the region. However, mage is an exclusive academic title reserved for certified spell-writers who have graduated from a mage academy.
History
After the Cataclysm, spellcasters shifted their focus to simple and practical combat magic in order to defend themselves from the newly-appearing monsters. Unfortunately, this means that much of the complex magic developed during the First Age was lost.
Once defenses were built and cities were established, people could turn their attention back to the First Age's utility magic. Scholars obtained artifacts from First Age ruins, cracked them open, and reverse-engineered the intricate spell circles inscribed within. Mage academies were established by these early scholars, to serve as hubs of information where they could share artifacts and research with each other.
The early academies often came into conflict with local authorities. Artifacts can be extremely dangerous, and governments didn't want these civilian scholars owning devices that could overthrow them. A few academies were destroyed or abandoned when the bans on artifact ownership went into full effect; others moved into the wilderness and eventually became cities of their own.
Mage Academies
In present day, there are 12 mage academies in Empyria - 7 in Orlis, 4 in Wywick, and Valefar Academy which is on neutral territory. Most academies offer a basic 4-year program after which students can legally call themselves mages, with a wide variety of postgraduate options if they want to continue their studies afterwards. Since magic is a broad topic with countless potential applications, most mages specialize in a particular category of spell, either by effect (healing spells, teleportation spells, etc) or magical taxonomy (spells requiring fire mana to cast, spells using a particular glyph, etc).
Since the "grammar" of a spell circle is fairly loose, there are many ways to arrange the glyphs of a spell and get the same final effect. Each school establishes its own conventions and rules for spell construction as their researchers communicate with each other, eventually forming a little programming language of its own. A knowledgeable and observant bystander can often determine which school a mage graduated from just by watching them cast.
Work
Spellwrights
Spellwrights are mages who write spells for a living. In the past, they were commissioned by companies or governments to devise spells with specific effects, to be written down and cast later by a non-mage. For example, a municipal government might commission and distribute a cooling spell to the citizens to reduce strain on the city's power grids during a heat wave.
As magitech became an increasingly important part of every life, many spellwrights switched their focus from human-castable spells to mana circuits. They serve as engineers and programmers, designing the circuit boards of magitech devices like appliances and phones.
In the past, most mages were spellwrights, and it remains the stereotypical mage job to this day. When most people picture a mage, they picture a stuffy old spellwright in flowing robes who writes spells for the nobility.
Battlemages
More straightforwardly, some mages work for the military. During times of war, they work in groups of a dozen or more to cast a single enormous spell together, raining fire upon the enemies.
While civilians can be wary of mages, seeing them as distant stuffy academics, battlemages generally get a better reputations. Particularly accomplished battlemages are essentially war heroes, showered with acclaim and awards wherever they go. Other mages tend to roll their eyes at this treatment, though - they know that high-powered flashy battle magic is among the easiest to cast. In fact, many battlemages go into the career because they can't find any other work.
Ruin Delvers
Ruin delvers are mage-adventurers who descend into First Age ruins, retrieve artifacts, and reverse-engineer them to further the study of spellcrafting. Being a historied occupation that is essential to the development of magical research, it is as prestigious as it is dangerous. Even the ruins of mundane First Age buildings were built for a society of mages with far more power and knowledge than even the most learned people in present day. Many security systems and machines with completely unknown purposes are still active, and threaten the well-being of careless visitors. Worse, the robots attacking you are also valuable artifacts and shouldn't be damaged...
Most delvers are full-time researchers at one of the twelve academies. A few non-mage adventurers try their hand at delving, too, and simply sell their finds to an academy; these unofficial delvers have a bad reputation though, being seen as innocently destructive at best and outright scammers at worst.