The role with the most capabilities is the head of household/primary admin. Only one head of household/primary admin user could be on a Sparklight Online Account. However, you can add additional users with other roles. Let's review what roles are available for users.
Head of Household /Primary Admin: Access to all functionality
Admin: Access to all functionality except changing out the head-of-household role or deleting the head-of-household account
Limited: View-only access, cannot add, edit, or delete users, can edit their account settings but cannot change their member type
Restricted: Same access as the 'Limited' role, except this role cannot edit their own settings