Why does the referral source always show as forms.zohopublic.com in Google Analytics instead of the actual source?

Why does the referral source always show as forms.zohopublic.com in Google Analytics instead of the actual source?

Use the Advanced UTM Tracking code provided in Zoho Forms to track the source along with the form submission. Refer to help for more details.

Case 1: If you are redirecting your form to the default Thank You page,

1. In your form builder, navigate to Settings >  Settings General > Thank You page & Redirection.
2. Select Add Google Analytics.
2. Click +Tracking Parameters as shown to map the UTM parameters.
     Tracking Settings
Case 2: If you are redirecting your form to a custom Thank You page,

1. In your form builder, navigate to Settings General > Thank You page & Redirection Redirect To.
2. Select the Prefill field values in website URL option and map form fields in URL parameters as shown.
Map form fields in URL Parameters