A simple, but useful bit on WHMCS is re-sending product emails. In this instance almost always product means web hosting given that is really the only product you would provide save for a domain depending on your school. Also, the only email you would really need to resend is the Welcome Email with their FTP credentials and other details. To do this login to WHMC and search for the user in the search box in the upper right-hand corner. Once you have found them, navigate to the Products/Services tab.
After that, at the bottom of that page there is a drop-down menu for re-sending email templates, you would want to re-send the “Hosting Account Welcome Email.”
This can also be done from the Emails tab by clicking the email button next to the “New Account Information” email:
After that they should have been sent another copy of their Welcome email.