Add a Survey question of type Net Promoter Score (NPS). The Net Promoter survey question needs to either display radio button or a sliding scale.
Currently the ClickDimensions Support survey has a very nice NPS question:
Online NSP Surveys. Retrieved from https://www.surveymonkey.com/mp/net-promoter-score/
Microsoft Voice of the Customer. Retrieved from https://docs.microsoft.com/en-us/dynamics365/customer-engagement/voices-of-customer/analyze-survey-data
ClickDimensions Survey. Retrieved from ClickDimensions email to me.
What is Net Promoter? Retrieved from https://www.netpromoter.com/know/