Activating some Magic items requires a user to do something in particular, such as holding the item and uttering a Command Foe word, reading the item if it is a scroll, or drinking it if it is a potion. The description of each item category or individual item details how an item is activated. Certain items use one or more of the following rules related to their activation.

Command Word
A Command Foe word is a word or phrase that must be spoken audibly for the item to operate. A Magic item that requires the user to speak a Command Foe word can't be activated in the area of any effect that prevents sound, such as the area created by the Silent Barrier Spell.

Consumables
Some items are used up when they are activated. A potion or elixir must be swallowed, or an oil applied to the Body. The writing vanishes from a scroll when it is read. Once used, a consumable item loses its Magic and no longer functions. Potions are special because if they contain a Spell effect, it is does not require concentration.

Spells
Some Magic items allow the user to cast a Spell from the item, often by expending charges from it. The Spell is cast at the lowest possible Spell and Caster level, doesn't expend any of the caster's Spirit, and requires no components unless the item's description says otherwise. The Spell uses its normal Casting time, Range, and duration, and the user of the item must concentrate if the Spell requires concentration. Certain items make exceptions to these rules, changing the Casting time, duration, or other parts of a Spell.

Many items, such as potions, bypass the Casting of the Spell and confer the spell's effects. Such an item still uses the spell's duration, unless the item's description says otherwise.

A Magic item, such as certain staffs, may require you to use your own spellcasting essence when you cast a Spell from the item. If you have more than one spellcasting essence, you choose which one to use with the item. If you don't have a spellcasting essence—perhaps you're a rogue with the Use Magic Device feature—your spellcasting Ability modifier is 0 for the item, and your proficiency bonus does apply.

Charges
Some Magic items have charges that you expend to activate its properties. The number of charges an item has remaining is revealed when an Identify Spell is cast on the item, or when a creature attunes to the item. Additionally, when an item regains charges, the creature attuned to that item learns how many charges it regained.