A referral program survey asks your engaged users whether they would bring a friend and what would make it easy. This template takes about 25 seconds: a yes or no on inviting a friend, the reward they would like most, and the way they would rather share, from a link to a QR code. Asking first tells you which reward to fund and which share option to build before any code is written.
It is written for a user's fifth session, when they know the app well enough to recommend it. In a web app, a custom event your code fires each session, with calls needed set to 5, opens it on the fifth (from Starter, or on 1 survey on Free). Inside a phone app, have the app open the survey's link after the fifth session. It also goes by email to active users, with the first question inside the message.
Results shows the share who would invite a friend, and a donut for the reward and for the share method with each share and count, against the period before. Choose Yes to see which reward and method the users most likely to invite chose. Add an open question, and Usertick reads each answer and files it under a theme from your list.