A Wand is used for casting spells in The Sims 4: Realm of Magic, but in contrast to what you might think, you do not actually need to own one to cast spell. However, they can be selected to be used when casting spells to give you a cool animation, so every Spellcaster should try to get their hands on a Wand they like.
Before you can get a Wand, you will need to travel to the Realm of Magic and become a Spellcaster. We already wrote guides about that, so click on the links for a detailed description. Anyway, the short story of it is to travel to Glimmerbrook and find the portal hidden beside the waterfall behind the Watch lot there. Click on this to get to the Realm of Magic, and speak to the 3 Sages there. Do as they ask you, and collect 7 Motes to give to them. That's all it takes to become a Spellcaster. So, the next step now is to get a Wand.
The Wands are actually sold by stores in the Caster's Alley. This is a small area with multiple stores, and they all have inventories that changes every single day. So one day one of the stores might sell Wands, and another store might sell it the next day. There will always be at least one store that sells a Wand, so you won't have to wait to be able to get one. So just keep checking the stores until you find one that sells a Wand.
When you purchase a Wand, it will be found in your inventory. You need to click on it in your inventory and select "Choose Favorite" in order to actually bind it to your character. After you do this, this Wand will be used for casting animations whenever you perform a spell or practice magic in the Sims 4: Realm of Magic. And that's it; the Wand is now yours, and you have it for as long as you keep it in your inventory. Enjoy!