To setup multi-factor authentication for webmail:
Sign in to outlook.office.com
with your ID and password, a login page appears (as shown below), click on "Sign it up now"
- Select authentication method to be "Authentication phone"
- Choose your country code and insert your mobile phone number.
- Select "Send me a code by text message"
- Click "Next"
- You will receive an SMS with a verification code, insert it then click "verify".
Save your "app password" in order to use it with email applications such as earlier versions of Outlook 2016 and Mobile applications.