Sponsored messages allow you to send highly targeted promotions directly to the people who have communicated with your business in Messenger. Sponsored messages may be sent outside the 24-hour standard messaging window, and will be labeled 'Sponsored' in the chat.
Sponsored messages can be sent in the following ways:
Custom audience should not be used for excluding users from receiving Sponsored Messages (for example, excluding users who have previously opted-out of receiving messages from you or for building a flow for users to unsubscribe from messaging) as Custom Audience is not intended to be used for this purpose. Instead, developers should direct users to native options within the message thread (desktop, mobile) to block messages.