A Default Survey as the name suggests will be displayed automatically to the members once they log in. It is a list of surveys that members will automatically get invited to, once they signup.
In order to add a default survey, go to Community >> Profile >> Default Surveys >> + New Default Survey
Once you click on the button, you will need to enter the following information -
Once you click on "Save", the default survey will be added.
You can perform various other actions too, like -
Yes, more than one survey can be added to the Default Survey list. A specific Default Survey can be displayed to the panel members depending upon their profile data and criteria set.