Updating message authorization code
With two-factor authentication, your account can only be accessed on devices you trust, like your i Phone, i Pad, or Mac.
When you want to sign in to a new device for the first time, you'll need to provide two pieces of information—your password and the six-digit verification code that's automatically displayed on your trusted devices.
When you sign in on the web, you can choose to trust your browser, so you won’t be asked for a verification code the next time you sign in from that computer.
To keep your account as secure as possible and help ensure you never lose access, there are a few simple guidelines you should follow: To use two-factor authentication, you need at least one trusted phone number on file where you can receive verification codes.
By entering the code, you're verifying that you trust the new device.
For example, if you have an i Phone and are signing into your account for the first time on a newly purchased Mac, you'll be prompted to enter your password and the verification code that's automatically displayed on your i Phone.
You can choose to receive the codes by text message or automated phone call.
When you tap Next, Apple sends a verification code to the phone number you provided.