How can we send email reminders ?

'Invites Tab' -> Click on the Candidate row -> click on the 'Send Candidate Reminder' widget -> Email reminder goes to the candidate

You can also go to the 'Assessments' tab and do the same:

'Assessments Tab' -> Click on the appropriate Assessment -> Click on 'Invites Tab' on left panel of the Assessment-> Choose the candidate and use the Action Strip, clicking on the 'Send Candidate Reminder'