How do I limit which accounts a teammate uses?

Settings → Accounts

1. 1
   Confirm the organization type

   If it is not enterprise or agency, the page says per-person limits come with Enterprise and with workspaces marked as an agency. The link is View billing.

2. 2
   Pick the teammate

   Admins cannot be limited. The page says an admin can see and use every repository and connected account.

3. 3
   Pick repos and accounts

   All repositories or Only selected repositories. All accounts or Only selected accounts. Save access writes it.