Tried to turn on 2 factor on IPhone 8 but the Password & Security page only has RESCUE EMAIL ADDRESS at the very bottom - there's no option to turn on 2 factor authentication. I'm also using MacBookPro running Yosemite 10.10.5 and I did not have two-step authentication turned on there.
iPhone 8, iOS 13
Some Apple ID accounts do not support 2 Factor Authentication. I suggest you contact Apple ID Support to see if they can assist you in enabling it on your account. See the Apple Support articles below for contact information.
Apple ID - Official Apple Support.
Contact Apple for help with Apple ID account security - Apple Support. (Link doesn’t always load)
Get Support Work through the screens to get a chat option.
See Two-factor authentication for Apple ID https://support.apple.com/en-us/HT204915 and more specifically the section entitled Can I turn off two-factor authentication after I’ve turned it on? You can't turn it off unless you recently updated your account. In this case, you can unenroll within two weeks of enrollment.
If you are in the two-week period, "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."
Apologies. I misread what you wanted to do.
2 factor ID
