If you have the auto-renew feature enabled on your domain, you'll receive the invoice for a domain renewal thirty (30) days prior to the next renewal date that appears on the client area. Either you have a credit card on file or PayPal automatic payments enabled the charge will be automatic. 

If you want to renew in advance, please contact our Billing Team and they will be happy to generate the invoice for you. 

Here you can follow the instructions in how to enable the Auto-Renew feature for your domain. 

Your credit card details can be updated by following these steps.