>> Login to mail.zoho.com as Super Admin. 

>> Go to Control panel--> User Details--> click on the email address--> and you can modify the IMAP and POP setting for all the users in the organization. 

However I have many users in my organization, it's not feasible to manually edit each record. How can I either select and mass enable IMAP or enable IMAP by default for any new user (then I will re-import all users).