The Two-Factor Authentication (2FA) option is available on the User Menu.  (This option will not appear for tenants using third-party sign-ons such as Microsoft or Google).

The User Menu is displayed by selecting the User icon on the Top Right of the Web Page.

Select Two-Factor Authentication (2FA) from the User menu

Selecting Two-Factor Authentication will open a screen to show the following: 

You will need to install an authenticator app, on your mobile phone (recommended) or computer.  Popular apps are Google Authenticator and Authy, with many more available.

The user can now either scan or copy the codes for their authenticator app and enter the authentication codes and press "Test Codes" to verify that your app has the key registered correctly.

The next time you log in, you will be asked for the code from your app.

2FA for any user can be disabled in the inmydata settings, by admin users only.