A verification code will be send by Google, when you have set a two time verification to your account. It will be normally send to your mobile phone. It will contain digits only. When you try to ace's your account, by entering your email address and password, the window will ask you the verification code. Just open the message that you've got from Google, and enter the digits you see there, as it is; and press 'Enter'.
It is a security measure against unauthorized log in to your account.
To turn off 2-step verification:
> Visit the Using 2-step verification page
under your Google Account settings
. Sign in with your username, password, and verification code if prompted.
> Click the "Turn off 2-step verification" link.
> A pop-up window will appear to confirm that you want to turn off 2-step verification. Click "OK".
Reference:Turn off 2-step verification
Gopakumar Gopalan Google