I view the elves as magical in every way. They are innately magical, and any high elf can innately spellcast. Each elf studies magic personally, like each olympic athlete trains, to master the talent to heights still unseen. The elven cultures celebrate, educate, and reward elves who excel at magic. I view elven government assemblies as magocracies, where the greatest mages become politically most popular and influential. Elves are like film and music superstars whose medium is magical arts.
5e has been going this way anyway, but probably the elf character can choose whichever ability they want for the spellcasting ability: Charisma, Intelligence, or Wisdom. Probably pick a cantrip from any class spell list.