There are several ways to go about adding additional licenses to your plan. Your Account Manager is the best person to speak to in regards to purchasing additional licenses or products.
Ways to contact your Account Manager
In-App, there's a quick and easy way to get in touch with your Account Manager.
To do this, you'll want to go to "Users" from the Admin Center.
From here, attempt to assign a license to a user, and the following will pop up:
If you press "Contact Sales" you'll be presented with a booking which allows you to schedule time with your Account Manager or launch a call in real-time if they're available.
Another option is to reach out to your Account Manager directly via their email, and they'd be more than happy to help you out!