1) Go to your Facebook page and select the Business Manager at the top of your page.
2) Click on Settings on the top right of your page's Business Manager.
3) Within Settings select Messenger Platform and scroll down to the bottom.
4) Find the Subcsription Messaging section and select 'Request'.
5) Select 'News' from the three options.
NOTE: You CANNOT send ads or promotional messages on Facebook messenger. You must make sure that you will be sending valuable relevant content to your fans.
6) Provide a short detail of what you will use the permissions for on messenger.
7) Provide 2 examples of messages that you might send to fans (NO ADS OR PROMOTIONS).
8) Select the checkbox at the bottom of the page and click the Save Draft button.