Hi I’m Bee. I’m very new to Stardew Valley. I have a decent world and I was wondering if I could use that already made world to host a multiplayer game? Sorry if this has been asked a lot.
Yes, if you have Robin build cabins on your existing farm you can then load that farm in the co-op menu and invite friends.
Go to robin she will give you the option to build a cabin there's 3 designs that require 100G and a certain type of resource like wood/fibre/stone.