There are a number of different items that you’ll find when playing the World of Light Adventure Mode in Super Smash Bros. Ultimate. These items can be used in another mode in Smash Bros. Ultimate called Spirit Board. This mode allows you to tackle different Spirits that are not found anywhere else in the game.
Note: If you are looking for a way to use these items in World of Light, you cannot do that. These items can only be used in the Spirit Board mode of the game and can not be used to make fights in World of Light any easier.
In the Spirit Board mode you will find that there is a new menu option on the screen when assembling your party. It’s a Battle Item icon and you can add one of these items to your party to make you more powerful. The good news is, spirits that you unlock on the Spirit Board can be brought into World of Light and can then be used in battles to help you in this massive single player mode. You can’t use Support Items in World of Light battles, but the Spirits you unlock on the Spirit Board can certainly help you regardless.
Regardless, if you’ve got plenty of Battle Items the place to use them is in the Spirit Board, which is ultimately a collection spot that allows you to build teams to tackle tough opponents with varying modifiers (similar to World of Light) in each match. While you cannot use these Support Items in World of Light, you can sell them for SP which can then be used to purchase things from the in-game shops in World of Light.
These Support Items from your World of Light inventory can be used for both in-match advantages such as Slow FS Charging, Draining Health, Disabling Items, Increasing Starting Damage, and Weaken a Spirit’s Minions and to do things like refresh the Spirit Board, Shuffle it, Change Spirit types, or rematch Spirits that you’ve lost to previously.