2-step verification must be enabled on the domain level. Then you will see the Two-Step Verification button in the Options – Accounts – My Account tab so you will be able to activate this feature and make stronger security for your City Network account.
The red cross next to the Two-Step Verification button indicates that you were not set up this feature yet.
Click the Two-Step Verification button and follow the instructions to turn on Two-Step Verification. You can select whether to activate this feature for your City Network account via City Network authenticator (available for iPhone and Android as well) or via SMS.
When you will go through the whole process successfully, the green mark indicates that this feature is set up and activated.
From now you will use the authenticator to sign in to your WebClient account.