No, the candidate does not need to sign up into EasyHire.me to take an interview.
When a candidate gets an invite to an interview (on-demand or live), he or she can access EasyHire.me interview room by clicking the link in the email.
This link is active only for 2 weeks. If the candidate wishes to view all his interviews in one place, then it is recommended that the candidate creates a login in EasyHire.me platform.