Customers who purchase their Google Apps for Work licenses through Promevo are able to add additional licenses directly through gPanel. These licenses will be added immediately to your Google Apps for Work domain.
This feature is located under Plans and Billing> Google Apps for Work > Overview > Manage Licenses in gPanel.
View more information on this feature in our gPanel help documenation.
Note: If you have not installed gPanel yet, instructions to do so can be found here