Priority Colo Inc.

How can my clients can access their individual web mail accounts without having to log into their domain's Cpanel first?

for IMAP:
mail.domain.com

for POP3:
mail.domain.com

for SMTP:
mail.domain.com (port 25 or 587)

for Webmail:
www.domain.com/webmail

for all the above:
username: emailaddress@domain.com
password: whatever you provide for that email address

All the above applies to Outlook, Thunderbird, Eudora (RIP), Internet Exploder, Firefox, Opera, etc.

That was simple. I don't know why I couldn't figure it out myself.

I appreciate your help.

You're welcome.

I should have added that there's also a secure webmail link, which is:
https://www.domain.com:2096

Don't forget the https at the front of the link, and the :2096 at the end.

Take care.