The Members tab of your organization's settings
(/orgs/{your-org}/settings/members) lists everyone in your organization
and lets Managers and Owners manage who has access.
The member list
For each member, the list shows their name and email, their current role, the date they joined, and who invited them (or nothing, for the person who created the organization). Every member with the Reader role or above can see this list, including read-only members.
Changing a role
If you can manage members, each row shows a role selector instead of plain text. You can only assign a role up to your own level: a Manager can grant any role up to Manager, and only an Owner can grant Owner. A change can be refused for two reasons: assigning a role above what you may grant, or assigning a seat-consuming role while your organization is already at its plan's seat limit. See Roles and permissions for what each role can do, and What counts as a developer seat for how the limit is calculated.
Removing a member and leaving
A Manager or Owner can remove any other member from the list; removing yourself is not offered there; use the leave action below for that. Any member, regardless of role, can leave the organization from their own row.
Both actions open a confirmation dialog before they take effect. An organization always keeps at least one Owner: removing or demoting the last remaining Owner is refused, and the last Owner cannot leave without first transferring the role to someone else.
Seat usage
Above the member list, a summary shows how many seats your plan is using out of its limit, or that usage is unlimited on plans without a seat cap. Next to it you find a link to your organization's billing page for plan details and upgrades, and, if you can invite members, a link to send new invitations. See What counts as a developer seat for the full definition of a seat and what happens once you reach the limit.