Note to disable two factor authorization

If you enrolled less that 14 days ago, open your confirmation email and click the link in it 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.

If its been more than 14 days or this is an Apple ID of recent creation, it cannot be turned off.

With that said, it should be mostly transparent in every day use.

The only time you should see it, is when logging in to a new device for the first time, or logging in to an Apple secure website such as https://iCloud.com or https://appleid.apple.com from an untrusted browser.

More info by clicking here -> Manage two-factor authentication for your Apple ID from iPhone - Apple Support