I want to upgrade my iCloud storage
I changed my email address last year but, I still seem to have the old email and I don't remember my old password.
[Re-Titled by Moderator]
If the email address was an Apple ID and you had set up iCloud Keychain Set up iCloud Keychain - Apple Support , the password would have autofilled in the keychain access of Mac and it can be viewed View the information stored in a keychain on Mac - Apple Support