How to get a prefab (reference) at run-time

I have 7 prefabs that appear randomly and I would like to control all this in code. The idea I have is as follows:

  1. To define a variable of type GameObject.
  2. Get one of the several prefabs I already have into this variable.
  3. Instantiate it and place it on screen.

The code below represents such an idea in a very general way, so only pay attention to the concept.
According to Unity3D documentation, the Find method should not be used within the Update method. My primary goal here is to determine how to get the prefab in order to instantiate it at run time.

Best regards,
Jorge Maldonado

public class EnemyManager : MonoBehaviour {

        public GameObject prefabObject;

        // ************************************************************
 	// Executes once before the first Update.
 	// ************************************************************
 
	void Start () {
		// some code here
	 }
	
 	// ************************************************************
 	// Update is called once per frame.
 	// ************************************************************
 	void Update () {
            //some code here
            prefabObject = GameObject.Find("asteroid01");
            GameObject.Instantiate (prefabObject, new Vector3(10, 10, 0), Quaternion.identity);
            //some code here
 	}
}

https://docs.unity3d.com/Documentation/ScriptReference/Resources.Load.html