Turn off 2 factor authentication

From the article below. If it has been on longer than 2 weeks, you can't turn it off. 

Can I turn off two-factor authentication after I’ve turned it on?

If you already use two-factor authentication, you can no longer turn it off. Certain features in the latest versions of iOS and macOS require this extra level of security, which is designed to protect your information. If you recently updated your account, however, you can unenroll for a period of two weeks. Just open your enrollment confirmation email and click the link to return to your previous security settings. Keep in mind, this makes your account less secure and means that you can't use features that require a higher level of security.

Apple ID -Two-factor authentication.   *

If you see a password box, enter the password (ABC) followed by the code (123) or ABC123 (no spaces).

Something to try, as this works with many older devices…

Append the two-factor verification code at the end of your password.

Enter your Apple ID and password on the Apple TV prompt, but do not press return on the password.

Using an iPhone or iPad:

• Settings > iCloud > Apple ID
• Select Password & Security
• Select Get Verification Code

Append the verification code directly onto end of the previously-input password, and press return.

if your password is ABCDEF and the verification code is 123456, the password Iinput should contain ABCDEF123456

The verification code doesn’t last very long, so the above is how you can authenticate within the available timeout.