To send a reminder specifically to those who haven’t completed their information in the signup form (not filled in), follow these steps:
Go to the event
Click on `Messages` in the menu
Click on 'Email'
Click on `Compose`
Fill in the content/text of the email under the Content tab
Click on the tab `Recipients`
Choose `Attending` under Send message to by checking the box
If there are attendees who have not filled in their information in the signup form when buying their ticket, the box Not filled in will appear
Check the box `Not filled in`. This way, the email will only be sent to the attendees who have not yet filled in all information on their signup form
When checking the box Not filled in, you can see that the number of attending recipients and email credits change according to the number of people with missing information.
To send the email, click the tab 'Send' and follow the instructions.