After you turn on two-step verification or set up the Authenticator app, you may run into issues if you use apps or older devices (like Windows Phone 8 and Xbox 360) that don't support two-step verification.
If you have two-step verification turned on and an app isn't prompting you to enter a security code when you sign in, you may be able to sign in with an app password instead. An app password is a long, randomly generated password that you provide only once instead of your regular password when signing in to an app or device that doesn't support two-step verification.
You only need to create an app password if you have two-step verification turned on and are using an app that doesn't support it.
If you forgot your password, are having trouble resetting your password, can't find your security code, or have other problems signing into your account, see When you can't sign in to your Microsoft account.
How to create a new app password
To create a new app password for an app or device, take the following steps. You can repeat these steps to create an app password for as many apps or devices as you need.
Go to the Security basics page and sign in to your Microsoft account.
Select More security options.
Under App passwords, select Create a new app password. A new app password is generated and appears on your screen.
Enter this app password where you would enter your normal Microsoft account password in the application.
Once you have created and entered an app password for a given app or device, you usually won't need to do it again.