How to put a health bar above enemy?C#

BugzergArcade's vids tutorial's he does what your asking.

One way to do it would be using `Transform.InverseTransformPoint(Vector3)` to transform a world point (i.e., the point in which you want the health bar to "float" on) to screen coordinates. Then you would use Unity's GUI features to draw a health texture for the bar, labels, etc. Here is an example:

 public class Bar : MonoBehaviour {
     public Transform barWorldCoords;
     public Texture barBackground;
     public Texture barForeground;
     public float health = 1.0f; // From 0.0 (no health) to 1.0 (full health)
 
     void OnGUI() {
         Vector3 screenPoint = Transform.InverseTransformPoint(barWorldCoords.position);

         // Draw Background
         GUI.DrawTexture(new Rect(screenPoint.x-100, screenPoint.y-20, 200, 40), 
                         barBackground, ScaleMode.StretchToFill, true);
         // Draw Foreground
         GUI.DrawTexture(new Rect(screenPoint.x-100, screenPoint.y-20, 200F*health, 40),
                         barForeground, ScaleMode.StretchToFill, true, 
                         ((barForeground.width*health)/barForeground.height));
     }
 
 }

This isn't tested, so it might have bugs, but you should get the general idea from it.