Frequently Asked Questions
What is a two-factor authentication? How does two-factor authentication affect my Apple ID?
Apple has created a two-factor authentication to add extra protection for your Apple ID. Two-factor authentication requires two pieces of information. So even if someone knows your password, two-factor authentication will require your password and a code from one of your trusted devices.
Apple's support page has more information on two-factor authentication and how to enable or disable it.