Magic flows from the realm of creation or better known as the divine realm into the veil the Infinite metaphysical barrier that separates the divine and mortal planes.
@Dragon Lord are the magic made flesh immortal and undying able to use magic naturally without a source.
The races of elves which includes @Twilight Forest , @Wood Elf , @Goblin are capable manipulating magical sources using that to cast spells and weave enchantments.
@Human are not born with the ability to cast magic. Only through runic magic are they able to cast spells. Human mages use spellbooks or items carved with runes.
The art of using runes to focus magic and cast spells. The more complex the layers of runes the more powerful the spell can be cast.