Microsoft has offered two-step verification (2FA) process since early 2013. Also known as two-factor authentication or two-step authentication, the process strengthens your account security by requiring you to enter your password (step 1), then a security code (step 2). The security code can be sent to you by e-mail, SMS, phone call or you can use an authenticator app on your mobile device.
Enabling two-step verification on your Microsoft account will enable it across all Microsoft services that currently support two-step verification, like Windows, Outlook.com, Office, and SkyDrive. Here's how to get started:
Enable two-step verification
Step 1: Go to this Account Settings page, and look for both an email address and phone number under the section titled "Security info helps keep your account secure." If either piece of information is missing, click on the Add security info link and follow the prompts.
The SMS functionality of 2FA relies on your phone number being connected to your account, so don't skip it. Otherwise you'll need access to your email account to receive your secondary log-in code.
Step 2: Click on the "Set up two-step verification" link.
Step 3: Follow the setup process until you reach the end, then click "Done." You may be asked to provide a verification code, sent to either your phone via SMS or to your alternate email address, before you can complete the two-step setup. Once it's complete, you should receive an email confirmation from Microsoft sent to your alternate email address.
Pair an authenticator app with your Microsoft account
You can get security codes by email, phone call or SMS, but an even easier way is to use an authenticator app on your mobile device. Authenticator apps, like Google Authenticator, run locally on your device and work even if your device doesn't have an Internet connection. To use an authenticator app, you first have to pair it with your Microsoft account.
Step 2: Go back to your Microsoft account security info page, and you should see a prompt to setup an mobile app. If not, click on "Set up identity verification app" link under the Identity verification apps section.
Step 3: Launch your preferred authenticator app, then scan the bar code on the screen.
Step 4: When the security code appears in the authenticator app, enter it in the box, then click on the Pair button.
Using two-step verification
Once you've enabled two-step verification on your Microsoft account, logging in to your Microsoft services will require your account password and a security code. Fill out the required information (usually the last four digits of your phone number, or a portion of your email address) to trigger the security code being sent to your device. Otherwise, launch whatever app you used to set up verification codes (Google Authenticator, for example) and then enter the code in the text field.
Lastly, some apps and devices don't support security codes. In those instances, you can go to the security info page and create an app password to log in.