I have made a third person among us game and I want to make it a online multiplayer. However, I do not want to publish it. How can I share my game with my friends without publishing it? and how do I make it multiplayer?
You would use a networking library to make it multiplayer, the popular ones:
Photon Bolt (my suggestion, and it’s very programmer oriented with generic types, strongly typed events, built in lag compensation and bit compression, etc) Photon BOLT Engine, perfect for Steam & PC
Photon PUN2 PUN 2 - FREE | Network | Unity Asset Store
Mirror https://mirror-networking.com/
I like the Photons since they have relay, which I think you want if you want to allow the local PC to host games. Otherwise, if you spin up servers using Playfab GameServers or AWS Gamelift, you won’t need relay and you could use any library. PUN2 does give some automatic support of host migration, which if you don’t want your game to end immediately when the host quits (again this only applies if you want local players to be run hosts) then you might look at PUN2.
For freely sharing the game via a patcher/updater service so you can easily post updates and everyone can make sure they have the same version, you could use Itch.io although i’ve had issues with it, and I use PatchKit.net instead for my games. So I recommend Patchkit.net all you have to do is ask them for the free indie plan via email.