Can someone explain what are sessions and how they work? or What are sessions and why are they import

What are sessions?

Hey guys, total noob here trying to wrap my head around this.

So like, what are sessions? I keep hearing about them in web dev but don’t really get how they work. Are they just cookies? Or something else?

From what I *think*, they help keep track of users on a site, like when you log in and it remembers you. But how??

Also, why are they so important? Pls explain like I’m 5 lol.

Thanks in advance! 🙏

(ps. if this has been asked before, my bad – point me to the right thread!)