The best way to set this up is to put the tracking script on the thank you page that they are directed to after filling out the sign-up page, that will track every person that fills out the form. The tracking script is only for InviteBox campaigns with goal-based rewards, referral contests, and sweepstakes. To see the tracking script at the integration step, conversion needs to be picked as the goal. In InviteBox, conversion means the referral visited a certain page with that script, so the original participant can earn a conversion point. For example, it can be your "thank you" page users see right after the purchase or sign-up. Normally this page should not be available for those who did not complete the necessary action or conversion in this case.
Also more advanced and imaginative InviteBox customers that can involve developers into the integration process can write code to execute the InviteBox conversion script when some event happens on their side. For example, if the user uploads some content, leaves comment or anything they can fancy.
The default process looks like this:
Participant enters campaign -> Spreads his unique link -> his friends click
on this link and visit the landing page -> then they perform the required action
(e.g. register) -> see the thank you page after registration -> original
participant earns 1 conversion point.