I set up a zohomail Lite account a little over a year ago (happy camper here) using the zohomail.com domain.  I would now like to add a new account for my wife as a separate email address (still @zohomail.com) and a completely separate inbox.  I don't care if the billing happens at different times or both are billed on the same date annually.  I cannot for the life of me figure how to do this.  I go to the Users tab and click +Add (as directed by some zoho help instructions) and it tells me to "Add a domain to add users".  So, I want to give zoho some more business but I'm finding it very difficult to do so.

Any guidance?