off two-factor authentication

Do you mean turn it off? Two-factor authentication is enabled by default on new Apple IDs and cannot be turned off.

If you have an old account and recently activated Two Factor Authentication note this section of an Apple support article:

"Two-factor authentication for Apple ID" - https://support.apple.com/HT204915

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

... If you recently updated your account, you can unenroll within two weeks of enrollment. Just open your enrollment confirmation email and click the link to return to your previous security settings ..."

If you're trying to turn it off, it can't be done.

There is a short period just after turning it on that is possible to disable it. After that, it's on for life as you can see in this article Two-factor authentication for Apple ID - Apple Support down below.