Can I buy WoW game time for someone else?

I'm curious, is it possible for me to purchase World of Warcraft (WoW) game time for someone else? I understand that players often need to renew their subscriptions to keep enjoying the game, and I'd like to gift this to a friend. Is there a straightforward process for doing so, or are there any restrictions I should be aware of? Additionally, how does the recipient redeem the game time once I've made the purchase? Any guidance would be greatly appreciated.