Ammo world is the same as Ammo regular but the fragrance is different and more discreet. Ammo summer has additional pheromones aimed for younger people and is also more discreet smelling. These are the differences between Ammo products.
Regarding application points, you can read this thread:
Application points 101: a guide to where on the body to apply pheromones
Just remember that IHonesty must be applied to your wrists or hands, never near face or you’re in for potentially unwanted self effects (you might talk too much and say what you don’t want to say).