In order to link ArcMap and ArcGIS Pro with the WebOffice author standalone, you must click on Install ArcMap Connector Extension and Install ArcGIS Pro Connector Add-In during the installation of the WebOffice author standalone to install the corresponding connector add-ins.

 

ArcMap Extension

Open ArcMap and choose Customize -> Extensions. Tick WebOffice author standalone. The ArcMap extension is now connected with WebOffice 10.9 R4 author standalone.

ArcMap Extensions

 

Now the WebOffice author standalone can be selected via Customize -> Extensions -> Toolbars and the toolbar can be integrated.