Organization Owners and Organization Admins are allowed to add team members. After creating a team, navigate to Organization Settings > Teams tab and open the team to view the team’s details. Click on "Add a team member" and choose which users to add to the team. Users can only be added to a team if they are already members of the organization. When a user is added to a team, they be able to access all spaces inherited by the team.
If you would like to add a user to a team which isn’t already a member of your organization, Invite the user to your organization and select the team on the invitation page. Once the user accepts the invitation, they will automatically be added to the team, and inherit all space memberships held by the team.