To get access to the activation of 2-factor, you go to your profile. Click on the profile circle in the right corner with your initials or image. Inside the profile, click on the settings link (cogwheel icon).
Scroll to 'Account Detail', Then click on the switch button to enable 2-factor authentication.
When it is activated, press create new enrollment under the 'Two-factor authentication' section.
You will then receive a link that will send you to the login page. There you can use your Google Authenticator app, or a similar app, to scan a QR code to add 24SevenOffice.
Once you have done that, you must enter the code and then you will receive your recovery code. It is important that you store this in a safe place in case you need it later. You can also generate a new code later in the profile if you need it via the recovery code button.
It is important that you save this code somewhere you can easily find it again if you need to restore 2-factor
The next time you log in to 24SevenOffice, you will be asked to enter a 6-digit code. You can choose whether the system should remember the 2-factor authentication, then you don't have to do this every time if you don't want to. Then the system will remember it for a period before you can verify yourself again.