how do I turn off two-factor authentication on my iphone 12pro?

See this paragraph, extracted from the section "Turn on two-factor authentication" in this support page:--> Manage two-factor authentication for your Apple ID from iPhone

"After you turn on two-factor authentication, you have a two-week period during which you can turn it off. After that period, you can’t turn off two-factor authentication. To turn it off, open your confirmation email and click the link to return to your previous security settings. Keep in mind that turning off two-factor authentication makes your account less secure and means you can’t use features that require a higher level of security."

Regards

Giulio