I created a game with a server and client, and I do not know how to host it online(since my friend wants to join the game and we are not in the same network). If you guys know how please answer in the comments
Well, you have to host it locally(on 127.0.0.1) if you want it on your LAN. If you want it worldwide, you have to port forward.
How do I port forward?
If you only want your friend, just port forward and host from home.
If you want more people, you will need a proper server.
I would recommend getting a VPS.
Well, that usually costs money. Really, if your network protocol is good, you can host from home. A decent MORPG should only take around half a kilobyte per second, maybe even less. Its all about how you control the packets you’re sending. 
But then again, even getting DOSed at home(by bad people) isn’t really good idea.
A VPS these days isn’t that expensive, especially if it’s just an experiment and you don’t need a lot of resources. Hosting at home is bad.
You can get DDoS.
You can’t turn off your computer or router.
You’ll get complaints when it’s down.
Etc…