The WebMap I used in the Map Viewer Template contained a Feature Service. My problem is the Search button did not even show on the MapViewPage. I found this
on this website:Configure Map Viewer—AppStudio for ArcGIS (Desktop Edition) | ArcGIS, but I cannot find "identify" under Mapping or Feature Access Capabilities when I published the Feature Service. I checked Data, Map and Query under Mapping Capabilities and checked Query, Sync and Update under Feature Access Capabilities in my case. I also published a Map Service with Data, Map and Query under Mapping Capabilities checked and used it in the Map Viewer Template, and the Search button worked.
Does anybody know why the Search button works for Map Services but not for Feature Services in the Map Viewer Template?