Mages use the mana in the atmosphere to use magic. There is an infinite amount outside the body and as long as the mage can create the correct symbols then magic can be used.

Taking in the mana into their body I'd augmentation. The mana travels through the 720 mana channels and the 8 arteries. No symbols are needed for augmentation but there magic has a limit. They can only use however much their body is capable of holding

Mages

Mages are beings that are capable of altering the mana in the atmosphere to become whatever they want. Everyone is born with an Affinity to an element, however only the truly gifted are able to bring out its power.

Mages are divided into multiple tiers, starting from; Initiate > Novice > Skilled > Master > Magnus

All mages learn to use the four primary elements; Fire > Water > Earth > Wind. Before they dive into the more advanced elements.

There are basic, advanced, superior, and impossible tier elements. With every tier being harder to control and master. Most mages are only able to use the basic elements with a few being able to use advanced and superior elements. Only one known person was able to use an element thought to he impossible.

Mages can only use magic with the mana in the atmosphere not anywhere else. However, in order to do so mages must be able to see the mana and harness it for usage. It takes a lot of focus and a strong will to use magic. The more complex the spell and higher tier the element, the greater focus is required. More complex signs need to be formed in order to use such magic. 

Mages are either rogue or certified. All certified mages are documented by the mage society, while rogue mages are not. It is illegal to be a rogue mage but not uncommon. Rogue mages learn unorthodox magic while certified mages attend academy to learn magic the correct way.