Magic, Mana, Magicka, Qi... In a sense they are all one in the same.
Magicka are a microscopic lifeform that reside within all living cells and communicates with Whills. We are symbiotes with magicka. Life forms living together for mutual advantage. Without magicka, life could not exist, and we would have no knowledge magic. They continually speak to you, telling you the will of the Whills. When you learn to quiet your mind, you will hear them speaking to you. Magicka allows us to sense the mana in the air, and for some even control it. In the surroundings mana usually has no element, however in some extreme environments the element of mana may reflect the surroundings. Normally the element of ones magic is determined by the magicka within you. There are 4 primary natural elements, fire, water, earth and air. The primary elements broadly cover most magic you can see, for example; ice, snow, cloud, rain, steam, blood, and plant magic can fall under water magic, however in some cases some lesser elements can fall under 2 primary elements such as cloud magic. There is also the elements of light and dark, they have gone through many different classifications throught history so they shall be referred to as special magic. Finally, the last 4 of the well known elements, the conceptual elements. Life, Death, Time and Space are naturally occurring yet in a way intangible. Most are unable to wield such magic as it requires a thorough understanding and not latent ability.
Qi is often used by those without sufficient magicka to use mana for magic. Qi in it's simplist form is circulated magicka, normally magicka only moves within ones body to cast a spell but for qi users it is constantly flowing. The flowing magicka strengthens the body and heightens the senses. For some qi may be used externally via an extension of the body, typically a weapon. Some who have years of experience may be able to use their qi to create an aura around their weapon, in the case of a sword it may "sharpen" the blade and in rare occasions do elemental damage.
Other than the natural magics there are also the unnatural magics, such as luck manipulation, buff and debuff magic (in some cases), and so on. essentially anything that doesnt fall under the 4 primary elements, the special elements or the conceptual elements fall under this category.
Those who cannot manifest qi or utilize mana can still harness otherwise supernatural powers, some may subconsciously use magicka to see mana, have visions of the future (slight dramatization), some may "manipulate" luck or even increase learning speed. Magicka can be used for much more than just magic, it is up to you to find your "magic" within.
No being is truly without magic, they mana not be able to utilize their magicka in any discernable or conventional method but it still affects them on the macro, and micro scales. It affects their fate and how they may chose to defy it. The monks of the far east are a great example of those without mach magicka, despite this however they manage to do great feats. The Kensai Monks have developed a way to "sharpen" a sword with their willpower. The Shadow monks also have developed a unique style, they are capable of blending into shadows, not with mana, but with qi. These examples are not one of a kind however, as such it means it is possible for others to learn techniques similar if not identical to the ones these monks use.
To cast spells there are a variety of options to take, each with their pros and cons.
Chanting: The duration of some chants can be lengthy but to counter that and the fairly high cost of mana the power is quite high.
Runic Circle: When drawn into the ground it takes a fairly low amount of mana to cast but doing so can be fairly difficult due to terrain, complexity, and other factors, but like chanting it can be quite powerful. On the other hand crating a runic circle with your mana is a bit costlier and weaker but is much quicker.
Visualization: The easiest way to cast magic for many, it has a low cost in mana and is almost as fast as you can visualize what you want the spell to do, however the power may be slightly lacking.