Street Fighter IV implements six attack buttons in the game; Light Punch, Medium Punch, and Heavy Punch (LP, MP, HP) and Light Kick, Medium Kick, and Heavy Kick (LK, MK, HK). The lighter attacks are executed faster but require the attacker to be closer to the opponent to execute properly. Heavy attacks have a greater range and do more damage than light attacks.
Special Attacks are the fighters' main abilities; the individual moves that are their signature and indicate their fighting style. This guide will use P for punch or K for kick when talking about special attacks, and PP and KK when an attack calls for you to press the button twice.