There are three possible statuses of your business account users. Those are Active, Deactivated and Invited. When you send an invitation to a user to join your team, its status automatically turns into Invited. When they accept your invitation, their status becomes Active. If you want to deactivate a user, go to the Users section of your business account, locate the user you need to deactivate and click the red stop sign to the rightmost of it. Note that only business account owners and holders of User Management permissions can activate and deactivate users. Also, only business account owners and users who hold Account Management permissions can invite users to a business account.