Subscriptions can be purchased during the regular registration flow. It is the final step in the registration process. If you would like to purchase a subscription at the same time you are creating your account to unlock the subscribed features from the get-go, all you need to do is follow the set-up steps until you get to the “Choose Your Plan” page. From there, simply select the plan you feel is the best fit for you, provide your payment details, and complete the purchase.
As a reminder, all subscriptions are considered non-refundable and will automatically renew until cancelled. Be sure you understand what you are purchasing before you complete the subscription process.