There are two schools of magic in the world, Blessed and Blighted. Being able to cast spells is an ability you are born with and your ability can typically be determined based on your ancestry.
Those who are Blessed are able to cast healing spells and other spells which improve the world around them. Those who are Blighted can only bring destruction and, as such, are shunned by society. The alignment, so to speak, of all spells in the Deluxe Edition core handbook can be found here.
Spellcasting can be done many ways, though all spells require either a verbal or a somatic component. Some spells may even require both. There are rumors of ways cast without either type of component, but those are completely unfounded.