This distribution channel is chosen when you send your invitations via paper, but you still want your respondents to fill out the survey online. You can use contacts to keep track of who has already responded and who hasn’t as well as look at your contacts’ individual responses. Since a unique URL is created per contact, the survey can only be filled out once via that URL.
If you want to invite the same person multiple times for the same survey, please follow the steps described in this article: Invite contacts more than once for the same survey.
Of course, it is also possible to let your respondents fill out the survey on a paper version and use contacts at the same time. Please contact our Paper Team for more information and a tender.
More info: Invite respondents via paper invitations