Each of the classes available to the player in Baldur's Gate 3 possess a variety of abilities and capabilities that allow them to explore the world and engage in combat. Each class can then choose a subclass, gaining abilities themed around that particular subclass that further diversify that character from others using that class. For the Wizard, the subclasses are known as "Schools," and one can be chosen for each of the eight schools of magic.
All Baldur's Gate 3 Wizard Subclasses, Ranked
Baldur's Gate 3's Wizard Class is able to specialize in one of eight schools of magic, gaining powerful benefits relating to that school.