How do 4X games work?

Excuse me, could you explain how exactly do 4X games function? I'm a bit unclear on the mechanics behind these types of games and I'm quite interested in understanding the fundamentals. Do they all follow a similar formula or do they vary greatly in terms of gameplay and mechanics? Specifically, I'm curious about the Explore, Expand, Exploit, and Exterminate elements and how they interact with each other in a 4X game. Thanks in advance for shedding some light on this for me.