To use the WhatsApp Business API, you must set up a payment method. Without a valid payment method, you cannot fully use the production features of the WhatsApp API. However, this process is not associated with immediate costs. Regular messaging is free. Fees may apply when using automated messages, templates, sending notifications, or for communication more than 24 hours after the last message. You can read more about WhatsApp API usage fees on the Meta pages.
Open your Business Portfolio (business.facebook.com) and in the menu click on Billing & payments.
Go to the Accounts → WhatsApp Business accounts tab and, for the WhatsApp Business account associated with the number you added, click Add payment method.
A form for adding a payment method will open. Once you fill it out, the payment method is set up.
