How can I provide a client with access to their email accounts I am hosting on cPanel?

Dumb question I know, but cannot seem to find a simple straight answer on this. I have multiple client accounts set up on cPanel... essentially they are external clients of mine for whom I host domains and email accounts. Is there a way to allow one of these clients access to their specific cPanel account only and not access my overall cPanel account? I want to allow this client to manage their own email accounts that I am hosting so they can set up their own email forwarding and create or delete email accounts tied to their domain name. Guessing this is related to Sub Users but cannot seem to figure out how to provide my client access to log into their cPanel sub account and access their email accounts.