Authentication

There is no means to disable two-factor authentication, if the account was created with two-factor enabled, or if two-factor authentication has been enabled on an older Apple ID for more than two weeks. If you’ve recently enabled two-factor on your Apple ID and now need to turn it off (within two weeks), check the mail message sent when two-factor was enabled.

If you've had it enabled for more than 2 weeks, you cannot disable 2 factor.

~Lyssa