Is there any way to migrate an existing series of emails from Outlook into my Zoho CRM account?
No, you cannot migrate emails in bulk from the Outlook Plug-in to your Zoho CRM account. The Outlook Plug-in, however lets you synchronize all your outgoing emails instantly with Zoho CRM.
When you install the Zoho CRM Plugin for MS Outlook, all your outgoing emails, calendar and contacts are synced. Keep in mind that only those records that have been created or modified in the past 90 days can be synchronized.
You can also sync your email account in Zoho CRM using the IMAP configuration.