If you are asking what is this, we wouldn’t blame you.  What it will do for you is secure your accounts from easy hacking. Â
We recommend you put it in place on your email and IT accounts (e.g. Gmail, office 365 etc.).
For instance, let’s say you have a Gmail account for your personal or work email.  You log onto it with a password and get in.  What if someone can guess your password, or has hacked you?  Alternatively, if when you go to login the Gmail sends you a text message and gives you a code to put in, which you then do as well as your password, how secure does that sound.  Read more about it here on Microsoft’s blog