You can protect your user account against abuse
What is MFA?
MFA (Multi Factor Authentication) is multi-phased authentication. In practice it means that you secure your sign-in with your mobile phone. The phone is usually always along so its use as a verification tool of the sign-in is quick and easy.
Bring MFA into use on yours own
First become acquainted with the verifying methods of MFA and think what of them suits yourself best. Then make the measures which are requested on the instruction page MFA, multi-factor authentication. After the measures, the MFA protection is in use on your O365 account in two hours.