...
Go to Manage > Discovery > Locations
Click New Location
Select Web Services
Choose ArcGIS Online / Portal for ArcGIS from the Type drop-down menu
Click Add next to www.arcgis.com in the Examples section
In the Configuration dialog, select Query under the Content heading
Enter query terms in the Query field (see next section for more information)
Click Save when you are done
...
When Voyager indexes the new ArcGIS Online location, it will apply the query settings added to the location's configuration.
...