For a client project, I created an account for an admin, a role ‘Admin’ with the permission to create and manage other admin.
When he tries to create a new admin, he can’t select a role (which exists) and cant save the new admin.
That’s expected. In OctoberCMS, an admin can only manage roles below their own in the hierarchy (check Settings → User Roles, where roles are reorderable).
If you’re on v3, the only way is to create a role that sits below “Admin” so it can be assigned.
If you’re on v4+, you can optionally disable strict hierarchy by adding this to config/backend.php:
'strict_role_hierarchy' => false,
This allows admins to manage users with the same role.