Lost recovery key and forget Apple ID password

From: How to generate a recovery key - Apple Support

- With two-factor authentication (the current security system) and an Apple device, you have the option to generate a recovery key to help improve account security.

- When you generate a recovery key, you can't use account recovery.

- "Using a recovery key is more secure, but it means that you’re responsible for maintaining access to your trusted devices and your recovery key. If you lose both of these items, you could be locked out of your account permanently."

- See the document for how to generate a key. Apple mobile devices and Macs only.

Use a recovery key

- If you forget your Apple ID password, you can try to regain access using your trusted device protected by a passcode.

- Or you can use your recovery key, a trusted phone number, and an Apple device to reset your password.