Multi-Factor authentication (a.k.a. MFA) is a method to help better email, Netsuite, Office 365 and other account access. This additional security comes from having to approve the sign-ins to your account using a mobile device. This way if a bad actor has somehow managed to get your password, they will not be able to access your email, since they will not have your device to approve the sign in.
Download link for: The Microsoft Authenticator App Do not set up the account in the App, until you are asking at login.
Methods Expanded:
Multi-Factor Authentication App Setup
Updating or Changing MFA Options
What A-Z Bus Sales applications will require MFA?
How often will I be asked to Approve my sign ins?