I would like to turn off two 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.       

Current services from Apple that require 2FA include:

Apple Card

Apple Pay

Home Kit

Messages in iCloud

iCloud Keychain (in newer IOS/OS versions).

If you’ve been using it for more than 14 days, it cannot be disabled. If less than 14 days, open the email you received when you enabled it and use the link there to disable it.

If you use messages in iCloud, iCloud Keychain, Apple Pay, Home Kit or any other service that requires it, and you disable it, you will not be able to use those services any longer.

The email would have come to whatever account you have as the primary email address for your AppleID.