1. You can open your Gmail account on your mobile where you are already logged in. You can go to the settings and access Google account recovery page. You can reset the password here and recover your Google account.
2. If you are using a laptop or desktop then you need to go to the Gmail login page first. After that you can enter your Gmail id and then click on "Forgot password".
3. Now you will be directed to the Google account recovery page where you can reset the password and recover your Google account.
Google account recovery number