To enable multi-factor authentication, go to “User settings” under your profile
Then click on Security
If you have not yet defined a phone number in your profile, you will need to click on the link shown below to do so:
Once a phone number is present in the profile, the number must be verified. Clicking on the link shown below will send an SMS to your registered phone number with a code that must be given as input:
Once you clicked Verify, you will be given the option to turn on user-initiated MFA:
Upon clicking Yes, this result will be shown in your profile and you will be prompted for MFA on subsequent logins: