From the customer view in https://admin.webex.com, go to Services and on the Message card click Settings.
Scroll to Webex AppHub and toggle the setting to off.
The app hub icon is removed from the Webex Teams app and the Add apps menu option in the space information menu is removed.
Remove the Webex App Hub Icon from Webex Teams
You can choose to remove the Webex App Hub icon from Webex Teams for everyone in your organization.