Two Factor Authentication is not enabled by default on the new CM Platform. Only the admin user is enabled by default and the extra users can choose to enable it or not.
CM provides users two-factor authentication to gain access to their account. This feature enhances the protection around your CM account and substantially decreases the likelihood of unauthorized access to your account if it was only protected with a username and password.
How to enable Two Factor Authentication?
The admin user can enable the Two Factor Authentication in the "Settings" app. You can find these Security settings at the Profile menu.
Click on your Name and click Profile

Choose the Preferences settings

Click on the enable Two Factor Authentication button

Fill in your Mobile Phone number and click update

Enter the verification code received by SMS
Congratulations you successfully enable Two Factor Authentication.
How to disable Two Factor Authentication?
Click on the disable Two Factor Authentication button

The Two factor Authentication has been disabled.