A first person shooter or ego shooter is a shooter game, that is seen from the view of a protagonist that the player plays as (hence the name ego shooter, the view from one's self). In contrast to third person shooters you can see yourself only in mirrors or on other reflecting surfaces. You may see parts of your hands or arms and carried items, but aside from this, nothing of yourself. Well known first person shooters are Counter-Strike or Unreal Tournament 2004.
This is a classic look for first person shooters, taken from Star Trek: Voyager Elite Force. You have some kind of hud, showing you details of the state or your character, such as ammunition and weapons carried, health or armour. Some games also have a kind of radar view, that may show the direction in which objectives are or opponents or team members. Classically there is some sort of cross hair at the center of the screen, showing you where your character is currently aiming at.