Before you can sign in to Office 365 with 2-step verification, your admin needs to enable it for your organization, and then you need to set up your verification methods. Once that's done, you're ready to sign in!
Sign in to Office 365 with your work or school account, and password.
After you enter your password, you'll be sent a code to your phone (or to whatever device/app you specified when you set up 2-step verification).
When you receive the 6-digit code, enter it in the box and then choose Sign in.
Tired of typing in 6-digit codes? Use the Azure Authenticator app on your smartphone for 1-click verification!