How do you buy a WoW Token?

Could you please explain to me the process of purchasing a WoW Token? I'm curious about the steps involved and any specific requirements or considerations I should be aware of before making a purchase. Is it a straightforward process, or are there any complexities I should be prepared for? I'm particularly interested in understanding how the transaction is facilitated and how long it typically takes to complete. Additionally, are there any limitations or restrictions I should be aware of when buying a WoW Token?