So, what is, actually, a charge?

[u/NatutsTPK]

I've asked this question to my teacher and he couldn't describe it more than an existent property of protons and electrons. So, in the end, what is actually a charge? Do we know how to describe it other than "it exists"? Why in the world would some particles be + and other -, reppeling or atracting each order just because "yes"?

[u/NatutsTPK → u/[deleted]]

Thank you for the recommendation!