Melee
Putting points into Melee will increase the damage from your Combat Styles.
Defense
Putting points into Defense will increase your durability by giving you extra HP.
Weapons
Putting points into Weapons will increase the damage from your Weapons.
Power
Putting points into Power will increase the damage from your Fruits.
How To Reset Stats
In Universal Piece, you can reset your stats for free by talking to the ResetStats NPC.

ResetStats NPC can be found on Novice Island (The starting island) and Solo Island. You can track them with the GuideTracker.

Press the fourth button from the drop down menu below your name to open it.
