Export the selection as an excel file using the below workflow.1. Click the query widget in Web AppBuilder for ArcGIS.2. In the related layer drop-down list, select the polygon layer.3. Specify the buffer distance in feet.4. Select a polygon in the map.5. Click Execute.6. Click the Results tab.7. Click the 3 dot in the Results tab.8. Click save to my content option. This saves a feature collection to my content.9. Publish this feature collection.10. Open the item details for the feature service.11. Click the export option and export to CSV.