Users are unlimited on every paid plan, so adding a person never changes the bill. What a login can do is set by its role and, for staff and clients, by the sites it is assigned to and a few switches.
Owner. The account holder, exactly one. Everything, including billing and closing the account.
Admin. Agency leads. Everything except billing and closing the account.
Staff. Only the sites they are assigned to (all sites, or a list). Switches: can spend credits (scans, briefs, writes), can approve and publish, can manage sites (connections, publish mode, content plan), can manage clients (invite client users to their sites). A new staff member starts with assigned sites only, can spend credits, cannot publish, cannot manage.
Client. Their sites only, white labeled. Switches: can approve drafts, can comment (request changes), can see Content Ideas (suggestions only). Clients never see credits, prices, other clients, API keys, settings, or the scanner’s competitor internals beyond the scores and the action plan. Plans without client portals have no client role.
Inviting someone. Settings, Users (owner and admins) takes an email, a role, the sites and the switches, and sends a link that creates or attaches their login. The link lasts 7 days. Anyone with the manage clients switch can also invite a client from that site’s client portal settings.
Existing accounts. When roles arrive, the current account user becomes the owner and existing client portal logins become client users on their sites. Nothing else changes.
Related: Content Queue; White label and client portals; Get support.