Once Multi-factor (MFA) it's enabled in the account, another menu option on the Profile sidebar will appear, called Multi-factor Authentication. We should click on Enable Multi-factor Atuhentication to start the flow:
Then, we would be able to setup our app of preference for Multi-factor Authentication, such as Google Authenticator, Microsoft Authenticator, 1Password, among others.
Once the Authenticator App it's setup, we should introduce the Verification Code, and then, MFA will be enabled in our account.
Next time that we are asked for the login, besides the password, we will be asked for the authentication code as well.