There's also the slightly more technical but mostly free route of running the dedicated server app on your own hardware. It's very lightweight compared to keeping the actual game running and can be permanently hosted on your gaming machine or maybe an old laptop you have sitting around.

the most flexible way, is by having the game hosted on a server, but, it does cost money, cause the easiest way is by finding a server host provider.

The other way is to leave your game running even when you're not there, assuming they're using different machines than yours. So, renting a server would be your best bet.