Seemingly everywhere you turn just recently everyone is implementing 2 factor/2 step verification, this is essentially a second step required to enable you to access normally password secured sites and services. Everything from your bank account to your web based email will shortly be secured using these new methods.
Each service has it’s own way of providing this second layer of security, your work VPN may have a code generating tokenkeychain, your bank may have provided you with a calculator and Google are now providing codes to your mobile device which you can use.
Each of the major services will hopefully contact you to set up your 2nd layer. For your Google accounts, you should be able to enable it now by visiting this link
It’s a good idea to enable this as soon as possible to prevent unauthorised access to your account.