Do you require 2FA to join your GitHub organisation?

If all members use 2FA in your organisation, the risk of unauthorised access to your repositories is lower. GitHub organisations can be configured to require all members to use 2FA to join.

1. Go to your organisation | Settings | Organization security
2. Under 'Two-factor authentication', select 'Require two-factor authentication for everyone in your organization'
3. Save

See the GitHub docs Requiring two-factor authentication in your organization