If your exam process starts with the delivery of emails to the candidates, having a prior knowledge of possible setbacks gives you a chance to solve problems by intervening. For example, when you send an invitation to a list, you may type several email addresses incorrectly. Being able to make the necessary changes by noticing possible setbacks earlier allows you to manage the exam process properly.
When emailing exam invitations, you can track to which email addresses the invitations have been sent. You will then be able to reach the information if:
for each email.