Want to pay the charges on your postpay threshold account? You don't have to wait until your next billing cycle. If your account balance reaches a minimum amount (for example, $1.01 if your account is billed in USD), you can make a payment at any time. (The minimum amount varies based on your account currency.)
To see the list of currencies and payment methods acccepted for your billing country/region, see How do I pay for Bing Ads?. And if you want to review whether a prepay account or a postpay threshold account works best for your needs, see What are my billing options? Pay now or pay later.
When you make a payment, your entire account balance is charged to your primary payment method. You cannot pay only a portion of your account balance.