Where to find my old iCloud password

If you are using Mac , open keychain access through spotlight , under iCloud section > passwords - search the old iCloud mail address - right click on it and again click on get info .

A window appears check the box of show password , again a window appears enter your admin password , the complete password for Apple ID can be read .

You can't, but you can reset your Apple ID password at https://iforgot.apple.com