I dont think this is a question for Mendix forum. Because you want to make the google form execute a REST API call.
So you must actually google for calling REST API from google forms. Except you are developing the REST API with mendix.
Any ways refer:
- https://stackoverflow.com/questions/53136247/google-form-make-post-request-on-submission
- https://badlywired.com/2016/03/integrating-google-forms-to-external-api/