Navigate to Account Settings > Email Settings:
Incoming Email
Server name: imap.zoho.com
Port: 993
SSL required: Yes
Email Address: Enter Your Zoho Mail address. If your domain is hosted with Zoho, then your email address will be in the format you@yourdomain.com.
Password: Enter your Zoho account password. (You might require an Application-specific Password if Two-factor Authentication is enabled).
Outgoing Email
Server name: smtp.zoho.com
Port: 465 with SSL
Email Address: Enter Your Zoho Mail address. If your domain is hosted with Zoho, then your email address will be in the format you@yourdomain.com.
Password: Enter your Zoho account password. (You might require an Application-specific Password if Two-factor Authentication is enabled).
OR
Server name: smtp.zoho.com
Port: 587 without SSL
OR
Server name: smtp.zoho.com
Port: 587 with SSL