This means that you did not assign any payment method in your Ad Account. Usually it is done at the Ad Account creation stage in Business Manager, but you can change these settings later:
There are two ways to pay for your ads:
You can assign your credit card (Please note that we do not recommend assigning virtual credit cards, like QIWI, due to Facebook’s protection from fraudulent activities). It can be done in your Ad Account:
Or you can sign a direct contract with us (we provide all the necessary closing documents) and make cashless payments.
To sign a direct contract with us, please write to firstname.lastname@example.org