To see who is in your organization, click the settings gear in the top bar, choose Organization settings, then Members in the left sidebar.
The Members tab lists everyone in the organization with their name, email, role (org admins carry an Org admin badge), the date they joined, and the user groups they belong to. Invitations that have not been accepted yet show Pending invite instead of a date. Use Filter and Search to find someone. The User groups and Resources tabs are where you manage groups and per-resource access.
Inviting people
Click Invite, enter one or more email addresses separated by commas, then click Next to choose their user groups and send the invitations.
Member actions
Hover over a row and click the ... button at its right-hand end. For a member who has joined, an org admin can:
Add to User groups - put the member in one or more user groups.
Set as Org admin or Remove Org admin - change the member's role.
Update email - if someone's address changes, update it here; they can sign in with the new address straight away.
Suspend account - stop a member from signing in, for example when they leave the organization. Everything they created, including items and comments, stays in place, and you can unsuspend them later from the same menu. You cannot suspend your own account.
For a pending invitation the menu offers Resend invite, Set as Org Admin, and Suspend account.
To act on several members at once, tick their checkboxes and use the actions that appear above the table.