>>11179555if you're minoring, you'll probably learn about Aristotle and Cicero. but actual work might be on the existentialists, since their views are still new-ish today.
Fun and educational to read are Camus' L'Étranger, and the myth of Sisyphus. I really suggest you start with Camus for the sake of minoring.
Also Aurelius' Meditations. They might help you understand contentment.
If you get interested in personal growth along the way, try out Kierkegaard and Nietzsche.
And if you really want to delve deep-deep on a 'what is existence' level you could read the Bhagavad-Gita. which learning Sanskrit for would be worth it, because translation and language sucks.
but i started with The myth of Sisyphus.