Magical Well

The area where a person stores their innate magical energy is called the magical well, or just the well. When a magical practitioner as asked to describe where they can feel it reside, they mostly say they can feel it about a hand span above the navel. It feels like a solid ball of energy that sits inside them. It can feel slightly different for different magic users. Some say it feels like a ball of light, or a roaring fire, or maybe a coil of lightning crackling within them. Some researchers have theories that this is to do with the element they most feel affinity with, but there is yet to be any proof of that discovered.
Every living human has a well of energy within them, but the size differs greatly from person to person. People who go on to be trained and experienced magic users will nearly always have larger wells with a usable amount of energy within. People with the small, nearly nonexistent wells will still technically be able to learn how to use magic. However, it will be exceptionally difficult for them and most do not manage. These people might well develop a few Cantraips of their own to aid in their daily life, but that is not a certain thing.
There is no way to enlarge a well as far as the majority of people or magic users are concerned. A very few individuals know of this secret method, but it is closely guarded and only practiced in secret.