Partners (agencies, developers) don't get invited like staff — their organization requests access to your store, and the request appears under Access Requests in Settings → Team.
Reviewing a request
Approving shows the permissions the partner asked for — you can trim them before granting, but not grant more than was requested. Requests expire if left unreviewed, and you can approve or reject several at once.
Managing collaborators
Approved collaborators appear in their own tab, where you can adjust their permissions (never beyond what their organization was granted) or remove them. Removing an organization's access requires removing its collaborators first, so nothing is left dangling.