Hello,
If you are looking to observe the console output while submitting a survey using the Survey123 field app on the same computer that you have AppStudio installed, you can do so by opening the Survey123 field app > select top right menu > Settings > Diagnostics.
If you are looking to observe the output when submitting a survey using the field app on a mobile device (iOS, Android), you can reference the documentation provided below...
Capture console output—AppStudio for ArcGIS | ArcGIS
Hope this helps,
Brandon