C# Floating Health Bar

Take a look at WorldToScreenPoint

  Vector3 screenPos = camera.WorldToScreenPoint(player.position);

Then you can use screenPos to set your texture on the right position

You can set your texture transform parent as the GameObject you want it to follow. For example:

 public GUITexture healthBar;
 public GameObject healthyObject;
 
 void Awake()
 {
     healthBar.transform.parent = healthyObject.transform;
 }

It is just an coded example for t$$anonymous$$s situation, you can also put the texture as c$$anonymous$$ld of the GameObject by the Unity Editor.

Setting it up, the health bar position will be related to the object position.