Players can't directly gift V bucks that Fortnite uses from one account to another. Epic doesn't allow it. If you want to gift something, you'll usually have to purchase the items with V bucks first and then send the item to someone. There are workarounds if you really want to gift V bucks though.
Can you gift V-Bucks on Xbox one?
There are some things you can't gift: V-Bucks. Real-money Offers (except Battle Pass) Items that are not currently in the Item Shop. Some additional offers such as Battle Pass Level bundles, Level Up Quest Packs, and Fortnite Crew.
How do you gift in Fortnite on Xbox?
Go to the Item you would like to purchase as a gift within the Item Shop. Select the item and click BUY AS A GIFT. Select recipient(s). Confirm your purchase, and your gift is on its way!
How do I transfer V-Bucks to another account?
V-Bucks are not transferable between accounts.
Can you buy V-Bucks as a gift online?
At MyGiftCardSupply, you can safely buy Fortnite V-Bucks Gift Cards online from anywhere in the world!
Can you gift V-Bucks you own?
Vbucks it's the in game currency and can only be bought or earned, but never gifted or donated.