How to replace my CRM's email with my newly hosted zoho mail.

How to replace my CRM's email with my newly hosted zoho mail.

Hello Team

I am completely confused with Zoho CRM account and Mail accounts hosted in Zoho mail.  

I have Zoho CRM account created with my private email. I have configured my company email in zoho  hosted  mail with our domain.

But now I don't know how to replace my CRM's email with my newly hosted zoho mail.

This is my 2-nd time to experience the same problem. 

Please help me.