A Key is a set of letters and serial numbers that you can redeem quickly and easily within the official video game platform in exchange for a digital copy of FUT 23.
After you redeem the game successfully, you can enjoy the game anytime you like.

This product can be global or include region restrictions that only allow you to activate it in specific areas of the world such as Europe, USA or UK.
As for the platform, steam, origin and xbox are supported at this time.
Check carefully! You can find the available region and platform for each product right next to the product name.

Your product will be delivered in several hours after payment. In the CDKey Order section of your U7BUY membership you will receive a digital code, also called CD Key, which you can redeem FUT 23 without problem in the official store.
To protect against fraud we occasionally hold orders. If this happens, your order will be reviewed and manually checked by one of our agents. It should be cleared within 24 hours, if we require any further information we will contact you via email.

Well the steps to activate FUT 23 with your purchased key is simple, it depends on the platform where you play the game too.
For detail instructions, please check this article in Help Center:
How to Activate a CD Key?