How do I Provide Mail Service alone to Clients in cPanel?

Linux Web host Control Panel has a option Feature Manager option to manage cPanel accounts allowed features. This interface allows you to edit feature lists, which you can assign to packages that you apply to cPanel accounts. Feature lists provide or prevent access to specific cPanel features.

cPanel & WHM includes the default, disabled, and Mail Only feature lists by default.

If you are a reseller who only owns a mail server, use the Mail Only feature list.

Home » Packages » Edit a Package » Choose the package which is allocated for the corresponding domain for which you need to give mail service only » Feature List » Mail Only » Click on Save

Once you saved you will be getting only mail related features in cpanel accounts.