Lost phone and iCloud

Hello karateSan,

Welcome to Apple Support Communities. We understand that you need to receive a two-factor authentication code to sign in to iCloud but do not have your iPhone.

Do you have any other devices that are signed in with your Apple ID? If so, you may be able to generate a code from that device. Check out Get a verification code and sign in with two-factor authentication.

Best of luck.

See a thread https://discussions.apple.com/thread/253465424

Note : in case if you have a new iPhone in which same Apple ID and password and account credentials can't be used , as credentials are still connected to old account with lost iPhone .

The old iPhone has to be removed from iCloud account , then you can you use the credentials in new iPhone , 2FA account is connected to hardware address of iPhone .

What respected community specialist suggests , please correct it .Say it would have happened , if a person has two or three iPhones and one of them is lost , he would sign in any of other iPhone with old credentials device ( that is being lost ) and get a verification code on new iPhone ( it doesn't work like this ) , apple has secured the account for every device with its credentials that are encrypted Security and your Apple ID - Apple Support

Hardware security overview - Apple Support

When you enter your Apple ID and password for the first time on a new device ( the statement from the first article ) .

This statement is applicable for fresh device when credentials are entered fresh , not connected to old device ( is short the lost device is connected to server it has to be removed from the account ) .