Subscriptions don’t need to be assigned to agents. Instead, surplus subscriptions are consumed as agents are added to MSPComplete. By default, every new MSPComplete account comes with three Get Organized plan subscriptions. MSPComplete will prompt you to purchase additional subscriptions if you add agents when all available subscriptions have been consumed. You can add agents as inactive and purchase subscriptions later, but those agents will not be able to perform actions in MSPComplete until more subscriptions are purchased. If you purchase more subscriptions, you can update agent roles to something other than inactive and the available subscriptions will be consumed.
Refer to these articles for more information about purchasing subscriptions, adding Agents, and changing agent roles: