On Champions Earth it's possible to learn nearly any style of magic one has ever heard of, from any source material. Typical comic-book magic is really just superpowers with distinctive trappings. "Super mages" may wave their hands and chant odd words, but that never seems to place any practical restrictions on what they can do and when they can do it. Like firing eye-lasers or palm blasters, their magic just happens when and how they want it to. Many real-world and fantasy magic traditions require more elaborate and lengthier preparations, and are riskier to practice. But in the Champions Universe you not only find magicians versed in fast, easy, powerful spells with colorful alliterative names (like the "Eleven Lights of Luathon"); but also practitioners of alchemy, kabbalah, voudou, Hindu yogic mysticism, Taoist sorcery, Native American shamanism, Norse rune magic, as well as fantasy-style necromancy, demonology, elementalism... just about the whole bag of tricks.
But if any would-be magicians on CU Earth are looking for an adult super-fied version of Hogworts Academy where they can go to study any of this, they'll be disappointed. To be sure, such things existed in the ancient past of the official setting, when the practice of magic was more wide spread and publicly acknowledged than in the modern era. But for many centuries before this one true magical lore was a guarded secret among a small number of practitioners, and that tradition remains largely in force in the present day, despite the presence of high-profile magical superheroes and supervillains. Most of the modern public doesn't believe in magic any more than in the real world, preferring more scientific (for comic-book-supers) explanations for the powers of avowed magicians.
Nonetheless, the precedents described for the setting suggest a number of possible routes an aspiring wizard can take to gain the power of magic. First, though, one has to have a talent for it. Not everyone can become an adept; like music or mathematics or handicrafts, some people are born with a natural affinity for the Arts Arcane. Magical talent appears to be rarer than any of those other abilities, but a fair number of people who choose to make the effort can learn a few simple spells or a particular magical discipline. But mastering power at the "super" level seems to require innate ability comparable to a virtuoso musician and composer. Mere study isn't enough. For example, the scholars of the Trismegistus Council, the CU's premier "good" occult organization, are among the most mystically-knowledgeable people in the world, but few of them wield actual power comparable even to a beginning superhero. (Even this restriction has work-arounds, though, as we'll examine later.)
Talent for magic sometimes manifests in minor ways discovered by accident. Black Rose, the leader of the Sentinels superhero team, was born of an Earth woman and a father from the magical dimension of Lythrum. As a child she learned she could open small portals to Lythrum, eventually enabling her to travel there and learn more Lythruman sorcery. Many people never progress beyond that basic level, or only in a very narrow discipline. Martika Duquesne, mother of Witchcraft of the Champions, discovered her aptitude for astral projection, and over decades has become very skilled at using it to spy on people, and to visit other dimensions; but has little magic skill beyond that.
Translating one's natural talent into practical power usually requires instruction by someone more experienced. The time-honored practice on Champs Earth is to find (or be found by) an adept in a particular style of magic willing to train you. Because of the secrecy common among magicians, finding the real thing as opposed to charlatans and con men is a difficult and time-consuming process. OTOH once you find one, and demonstrate your genuine talent and desire to learn, most adepts seem to want to pass on their learning to a worthy successor. It's not uncommon for a student to eventually surpass the skill and power of his or her master. Some of the most powerful and versatile magicians spend years traveling the world seeking multiple masters, so as to broaden and deepen their understanding of the Art.
Some agencies in the CU can function as a sort of "master class" in the deepest of magical lore. For example, the wizard known as the Eternal Tulku is reputed to be a former Archmage (Earth's premier mystic defender) who achieved extraordinary longevity. Tulku sometimes teaches magicians of proven skill, although since he suffers from dementia he won't waste his periods of clarity on any but the most worthy. The ancient serpentine race called the Nagas have vast occult knowledge, which they'll sometimes impart to mystics for their own (benevolent but mysterious) purposes.
Would-be wizards may find themselves in circumstances where it's much easier to locate a tutor. Among particular extended family groups, notably "occult dynasties" like the Vandaleurs and the Kayvanzadi, the talent for and practice of magic is much more common than in the general populace. A few distinct societies, like the Lemurians and the inhabitants of the dimension of Babylon, utilize magic in many of their activities. There are also cults, such as DEMON or Ouroboros, who teach their members particular spells or styles of magic as part of their "religious" training. Often these spells draw upon the power and reflect the qualities of whatever gods, demons, or other entities the cult propitiates or associates with.
A few Champions magicians learned magic entirely on their own through the study of arcane grimoires, sometimes attaining significant power, like Golem and Gyre of the Devil's Advocates mystic villain team. But without a more experienced mentor to supervise their experiments, these magical tomes pose great risk for the beginning spell-caster. More than one official novice mage has suffered serious unintended consequences from a spell improperly understood or executed. However, studying occult texts is one of the most common ways veteran super mages increase their knowledge and power.
Even rarer than someone with the capacity to be taught magic, is the so-called "wild talent," able to wield significant magic power without any formal training or study at all. Typically the wild talent's abilities are more narrowly focused than those of a trained mage. For example, Morgaine the Mystic, of the Crimelords team, is a wild talent with power over the four elements of traditional Western occult tradition.
Yet even if you lack the innate capacity for magic, you can still aspire to attain magical power. Some people can be imbued with the potential to learn magic by accident, such as Dr. Black and Dr. White of UNITY, who were changed after being kidnapped and nearly sacrificed in a botched cult ritual. They later sought out the veteran super mage called Eldritch for instruction in how to use their new abilities. Another well-traveled road to power is to make a pact with a supernatural being, for the knowledge and capacity to wield certain spell-like effects. Valerian Scarlet, the sorceress of Vibora Bay, bargained with a demon named Kerathios for her spell abilities. The typical down side to such a pact is that the empowering entity can remove these abilities if displeased with the pacter. And some of the most powerful magic users on Champs Earth, such as the Crowns of Krim villain team, have little to no magical knowledge or spell-casting skill, deriving their supernatural attributes from enchanted artifacts.
[The majority of the above setting-based information is derived from the PnP books, Champions Universe (describing the CU overall), and The Mystic World (focusing on the magic part of the setting). Supplementary material was drawn from Champions Universe: News Of The World, Vibora Bay, DEMON: Servants Of Darkness, and UNTIL: Defenders Of Freedom. Several of the villains mentioned above are fully detailed in the Champions Villains trilogy.
I also highly recommend The Ultimate Mystic, a scholarly but accessible and entertaining exploration of real-world and fictional magical conventions and traditions, and advice on how to translate them to gaming. It's by Hero Games, the publishers of PnP Champions, but for the most part isn't tied to the official Champions setting. Rather, it's designed to be inspiration for any game genre. It's mostly info and guidelines, with minimal PnP game mechanics.]