How the players making prefab object?

Questions & Answers
1

I hope that the players making prefab

Like Sims’ house, the player making an prefab object and share it with other people

How to achieve this function?

Is there a better way?

2

That implies saving a set configuration of gameObjects in a pattern so you can share it with other players. You can either use your own serialization using Json or XML or whatever, or use Unity’s AssetBundle system.