Instantiate By ID?

Hello, I'm new with the netcode. So I have a problem with instaniating an object through the network.

 [Command]
 public void CmdSpawnObject(GameObject objToSpawn, Vector3 position){
 
         GameObject newObj = Instantiate (objToSpawn, position+Vector3.up, Quaternion.identity) as GameObject;
 
         NetworkServer.Spawn (newObj);
 
 }

The Problem is, that it works well on the server side client. On clients it doesn't work, because I can't use GameObject as argument. Is there a way to get an unique id of the object from the prefab folder and find it by its id?