Add App Launcher and Notifications Components to Lightning Components in Communities
For example, you can create a custom theme layout component that uses the default Navigation Menu, but includes a forceCommunity:appLauncher component. Remember to hide the App Launcher that’s included in the default Navigation Menu by selecting Hide App Launcher in community header in the Navigation Menu property editor in Community Builder.
Alternatively, you can create a custom navigation menu that includes a forceCommunity:appLauncher component. Then you use this menu in a custom theme layout and include a forceCommunity:notifications component separately.