How does one get a new "recovery key" after being updated to 2-factor authentication?

Apple's instructions in this link are either wrong or outdated: https://support.apple.com/en-us/HT208072 My Apple ID is upgraded to 2-factor authentication. It does not utilize recovery keys. I have no idea what my old recovery key is, nor do I remember ever receiving one or authorizing the 2-factor system. Regardless, my current OS iPad does NOT show any option for "recovery key" in settings, contrary to Apple's 2018 instructions. My old, outdated iPad1 won't work until I provide the key, so...Apple, what now?