Approve iPhone from another device

So here's my situation... I created a new password for my iPhone 7 Plus and soon forgot it. I used my Mac to restore it and signed into my Apple ID, but now it needs my Old Passcode to enable iCloud. When I get to the Old Passcode screen and click "Forgot iPhone Passcode" it says either "approve iPhone from another device signed in to iCloud" or reset end-to-end encrypted data.

How do I approve the iPhone from my other device? Where would the option be?

Thank you for your help.