Forgot my APple ID for a new device

If you forgot your Apple ID password - Apple Support

If you forgot your Apple ID - Apple Support

How to use account recovery when you can’t reset your Apple ID password - Apple Support

Contact Apple for help with Apple ID account security - Apple Support

"Forgot my APple ID for a new device: How do I recover my Apple IF"

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Use these Forums' Credentials:

You are able to log in to these forums just fine. So, the credentials (eMail address and password) would be no different, given it is the same account.