You can edit the hosting package of your account, or if you have root access, you can also edit the package of other users from WHM.
1. Login to your WHM Account.
2. Go to Packages >> Edit a Package or type Edit a Package in the search box, and then the option will appear. Click on it.
3. Select the package you wish to edit.
4. Under Edit a Package, you can modify Resources like Disk space, Bandwidth, etc.
5. Click on the Save Changes button.