Spells. The regular part of now advanced human habitat. So much so that without it now, humans would surely won't be able to survive. It had been integrated deeply into every single one of their lives.
From technology to daily utility and transportation to healthcare and necessities. Everything was dependent on the very magic block, which formed most of the atmospheric layers.
The majority of humans themselves were capable enough to use distinct types of magic in some shape or form, from the moment they step into this majestic world.
And for those who could not use magic at all. It was just a matter of understanding. With a good mentor and a proper amount of training, every human was capable enough to use magic. They were made that very way from the start.