httpswwwgooglecomaccountsforgotpasswd

,Ifyouforgotyourpasswordorusername,oryoucan'tgetverificationcodes,followthesestepstorecoveryourGoogleAccount.,,,SetarecoveryemailaddressandphonenumbersowecanreachyouincasewedetectunusualactivityinyourGoogleAccountoryouaccidentallygetlocked ...,,Signin.UseyourGoogleAccount.Emailorphone.Forgotemail?CAPTCHAimageoftextusedtodistinguishhumansfromrobots.Typethetextyouhearorsee.

參考資訊如下
How To Attempt Google Account Recovery (LONG)

How to recover your Google Account or Gmail

If you forgot your password or username, or you can't get verification codes, follow these steps to recover your Google Account.

How to recover your Google Account or Gmail

How to recover your Google Account

Recovery email

Set a recovery email address and phone number so we can reach you in case we detect unusual activity in your Google Account or you accidentally get locked ...

Sign in

Sign in - Google Accounts

Sign in. Use your Google Account. Email or phone. Forgot email? CAPTCHA image of text used to distinguish humans from robots. Type the text you hear or see.