The licensing is based on the number of users who can simultaneously log into the form server.
The Server Configuration page displays your current installed license details. You update your license using this page. The form server will immediately update and run with the new license key.
To enter your license key:
The tenant admin for cloud customers can view the details of their current license by on the Online License page.
Options to modify/cancel your plan can be accessed by clicking on the provided link.
An option to Upgrade your trial tenant is available on the Manage Tenants screen.