My iPhone keeps prompting me to apply Two-Factor Authentication by means of a "notification" on the sleeping screen. I go to "Settings" and pull up that setting. It gives me choices of applying it or "not now," but none saying I don't want it. I select the "not now" and the "notification" is gone, but it soon comes right back.

I do not want Two-Factor Authentication. How can I make this annoying "notification" quit coming back?