Unity Organizations are the containers for your Projects and subscriptions. If you are an individual game developer, you might not need to work with the features provided by an Organization. However, to work with other team members, you must understand how to use accounts, Organizations, subscriptions, and seats.
Organizations are one way in which a collection of users can collaborate on Unity projects. An Organization can consist of a single user, and expand to include multiple users at a later time. You can associate multiple Organizations with your account.
A subscription defines the software license level available to an Organization. There are three subscription tiers: Personal, Plus, or Pro. For more information on requirements for each of the Unity subscription tiers, see the Tier Eligibility section of Unity Pro, Unity Plus and Unity Personal Software Additional Terms.
A seat represents an individual license to use Unity. When purchasing a Pro or Plus subscription, select the number of seats to purchase in that tier and then assign the seats to users in your Organization. You can also assign seats at a Project level to users who are not members of your Organization.