Change your payment method for Office 365 for business
When you purchase Office 365, you choose either to pay by credit card or pay by invoice. After you make this choice, changing your payment method – from credit card to invoice or invoice to credit card – is probably not as easy as you’d like, but it can be done by calling support and going through the purchasing process again. If you chose the credit card payment method, make sure you keep your credit card information up-to-date.
To change your Office 365 payment method
Wait while the support agent puts your subscription in a “canceled – reduced functionality” or “expired” state. Don’t worry, your users will still be able to use their services during this time.
While on the phone with the service agent, purchase a new subscription and, during checkout, choose the payment method you want to switch to.
After you complete these steps, your payment method will be changed and your users will continue to have the same license assignments as before.
If you want to change your payment frequency, either from annual to monthly or monthly to annual, you'll also need to call Office 365 support.