When you create a signup widget, it automatically creates a Widget Trigger (which you will find in a new scene in the Beat Sheet) and a verification email to be sent right after signup (found as an Action in the same row of the Widget Trigger. 

However, sometimes you create the widget, which creates the widget trigger, but not the email verification. Why?

This is because you haven't set up an email for your character yet. Conducttr will not create a verification email unless it has an account to send it from! So first give your character an email account (you can even select the "Do it later option", we just need the email placeholder) and then, create the widget.