Using a magic item to cast a spell is its own unique action type. Jeremy Crawford has said via Twitter that casting spells from magic items (scrolls, wands, staves, etcetera) is neither a Use an Object/Item nor a Cast a Spell action.
Do you need materials to cast spells?
There are some monsters which can cast spells with their innate spellcasting ability they do not have to provide any components. Unless stated otherwise if you cast a spell from an item you can do so without any components.
Do spells consume material components?
Does a spell consume its material components? A spell doesn’t consume its material components unless its description says it does. For example, the pearl required by the identify spell isn’t consumed, whereas the diamond required by raise dead is used up when you cast the spell.
Can anyone use magic items?
No gestures or spell finishing is needed, just a special knowledge of spellcasting that an appropriate character would know, and a single word that must be spoken. Spell trigger items can be used by anyone whose class can cast the corresponding spell.
Do you have to have material components to cast a spell?
If you have a component pouch, a spellcasting focus or a holy symbol (depends on your class), you can ignore all material components which have no indicated costs If you cast a spell from a spell scroll you do not have to have the material components
Are there any monsters that can cast spells without components?
There are some monsters which can cast spells with their innate spellcasting ability they do not have to provide any components. Unless stated otherwise if you cast a spell from an item you can do so without any components. (DMG, p. 141) Yes.
When do you cast a spell from a wand?
Casting the spell from a magic item (like a wand) also overcomes the need for a spell component’s use. The spell is cast at the lowest possible spell level, doesn’t expend any of the user’s spell slots, and requires no components unless the item’s description says otherwise.
Do you need a holy symbol to cast a spell?
Unless you have a holy symbol or arcane focus, which can substitute for some material components, you need to speak the words (Verbal) and make the motions (Somatic), and maybe dig into your component pouch for a spell component (Material), in order to cast the spell.
