configuring alias email address

configuring alias email address

I'm wondering here if paid zoho email supports email alias but free personal zoho email does not.  There is no add alias menu item visible as described in zoho help docs.  There is a personalize-send_mail_as and also email_forwarding_and_pop/smtp but I don't think these apply for aliases.

Here is my configuration:
  1. Thunderbird email client is using pop/smtp for email z@zoho.com.  It operates fine sending and receiving.
  2. An email system which owns y@y.com is configured to forward email to z@zoho.com. Email sent to y@y.com appear in my z@zoho.com mailbox.
  3. The goal here is to get the zoho smtp server to accept emails originating from thunderbird with email id from y@y.com.  Typically an email company like zoho will send a verification email with a secret for use in verifying ownership of the account.  I am never getting that verification email and am unsure how to configure zoho.