Different types of items can be used diffrently throughout the game. Use the following items to give your team an edge:

SKILL ITEMS Use these to activate players' skill sin the squad screen
BOOSTS Boost the rate that your players gain strength
RETRAIN ITEMS Retrain your players poitions or play style to match your style of play
LOOKS Unlock your players' star potential by applying unique looks
ACADEMY BOOSTS Use academy boosts to make sure you get the best out of your future superstars
TREATMENT ITEMS Get your injured players back on the pitch faster using special treatment items