Two factor authentication

You can’t turn it off. When you created your account it was enabled.

Two-factor authentication is an extra layer of security for your Apple ID, designed to make sure that you're the only one who can access your account—even if someone else knows your password. When you sign in with your Apple ID for the first time on a new device or on the web, you need both your password and the six-digit verification code that's automatically displayed on your trusted devices. Because just knowing your password isn't enough to access your account, two-factor authentication dramatically improves the security of your Apple ID and the data that you store with Apple.

Two-factor authentication is the default security method for most Apple IDs. Certain Apple services and features, such as Apple Pay and Sign in with Apple, require two-factor authentication. We recommend that you use two-factor authentication and protect your device with a passcode (or login password on Mac) and Face ID or Touch ID, if your device supports it.

Two-factor authentication for Apple ID - Apple Support

Hello,

I see you want to disable two-factor authentication. For some background I suggest you read the document: "Two-factor authentication for Apple ID" - Two-factor authentication for Apple ID - Apple Support

The previous posts say you cannot do this but we do not know the details of your situation. Depending upon when you created your account and when you activated 2FA you may be able to turn it off again.

Several years ago Apple transitioned to using two-factor authentication for additional account security. Accounts created since that time automatically use two-factor authentication and this cannot be disabled.

Some people have older accounts from before two-factor authentication was mandatory on new accounts. Apple encourages those users to transition to two-factor authentication when signing in on their accounts because without it "your account is less secure and you can't use features that require a higher level of security." An owner of an older account who has just now activated two-factor authentication has two weeks to change their mind and return to older security settings.

If you have an older account, recently activated two factor authentication, and you're within the two week period for turning it off again, you should check for an email from Apple for a way to do this. If you don't see one about this, look in your junk mail folder.

You cannot. See Two-factor authentication for Apple ID - Apple Support