Requires App Review.
The instagram_manage_messages permission allows business users to read and respond to Instagram Direct messages. The allowed usage for this permission is for businesses to retrieve threads and messages from its IG Direct inbox, manage messages with their customers or to use third-party customer relationship management (CRM) tools to manage its IG Direct inbox. You may also use this permission to request analytics insights to improve your app and for marketing or advertising purposes, through the use of aggregated and de-identified or anonymized information (provided such data cannot be re-identified).