Example of using Interfaces with MonoBehaviours in Unity

InterfaceExample.cs

using UnityEngine;

public class MyBox : MonoBehaviour, IInteractable{
      //We must implement this due to the interface
      public void Interact(){
        Debug.Log("I was interacted with!");
        Destroy(gameObject);
      }
}

public interface IInteractable {
      void Interact();
}

//Have me in a new file
public class PlayerInteract : MonoBehaviour {
  
    void Update(){
        //Get your gameobject somehow as ob
        IInteractable interactable = ob.GetComponent<IInteractable>() ?? ob.GetComponentInParent<IInteractable>();
        if(interactable != null){
          //You know you have an interactable object, something that had a mono that also implemented the interface
          //Be warned as if the object has more than one component implementing the interface you may need to get components and execute on them all.
          interactable.Interact();
        }
    }

}