Go to WHM > Packages > Add a Package. Fill out the values you want for your hosting plan.
I recommend "new" for the New Package Name, "10" for Quota, "100" for Bandwidth, and "unlimited" for everything else. (Do not change anything in the Settings area.)
Once done, click the Add button at the bottom of the page.
Now go to WHM > Account Functions > Upgrade/Downgrade an Account. Select your domain name and click the Modify button.
Select the name of your new plan and click the Upgrade/Downgrade button. All done!
Packages define the limitations of cPanel accounts that you create. The limitations which you may set are as follows:
Quota (MB) - Disk space in megabytes available for the cPanel account.
Bandwidth (MB) - Data transfer in megabytes available for the cPanel account.
Max FTP Accounts
Max Email Accounts
Max Email Lists
Max Databases
Max Sub Domains
Max Parked Domains
Max Addon Domains
As a reseller, it is a good idea to create multiple packages of different sizes. This strategy gives potential customers more options to choose from when they sign up with you. Also, with several packages, your existing customers will have options for upgrading as their hosting needs increase.
Packages also allow you to limit options available inside of the cPanel using Feature Lists. Creating a feature list is easy, in WHM, click on the "Feature Manager," select a name for the new feature list and click "Add." The next screen will have a long list of features that you may disable by removing the check from the box next to the name of the feature.
Feature lists may only be applied via the package that is associated with the cPanel account. If you have 5 cPanel accounts that are all set up on the same package and you wish to change the feature list of only one of those cPanel accounts, then you must create a separate package for that one cPanel account and assign the new package to the desired cPanel account.