1. Basic Settings
1-1.TEXT based authentication (Default)
1-2.Mobile App based authentication (Recommended)
We strongly recommend setting up more than one verification method. For example, if you travel a lot, consider for Microsoft Authentication APP your verification method. It's the easiest verification method to use, and a way to avoid text or call charges.
2. Additional Setting (for Outlook Mail User)
When multi-factor is enabled, outlook mail client (i.e. outlook 2016 etc) needs a "uniquely generated password" to keep logged in for your workstation. This is important because outlook client does not support a multi factor authentication and thus you require "uniquely generated password".