For pre-filling the star rating field via URL parameters, the Field code can be found under the Advanced properties.
For star rating field, we have Start and End limits. The value for the URL parameter should be within the start and end limits of the field. If the value provided is greater than the end limit value, then the end limit value would be used.
The field code can be used in URL parameters, as shown below.
https://example.neetoform.com/8abc2aa31ef7d12f288e?customer_rating=4
