Go to Messenger > Platforms > Web > Show the Messenger Launcher and toggle off the option to show the Messenger launcher for users or visitors. 

This disables the launcher in your app (or on your website) which allows your users to contact you, and see their past conversations with you. Your Messenger visibility settings will also apply to the Messenger on your Help Center.

You can also disable it by removing the "config.inbox.style = :default" line from the rails gem.

You can also completely customize the launcher – here's how to do it. 

All your outbound in-app messages are still delivered to your users even when the Messenger launcher is disabled. 

Your users will see these messages and can engage in conversation with you, but as soon as they've read or dismissed them, they won't be visible to the user anymore. 

These will be available to view if the launcher is turned back on.

You can hide the Messenger launcher in your mobile app. Here's how: 

You can also control which types of visitors and users can see the Messenger on your website, so your sales team can chat to more of the types of leads you want.