2 Step Verification increases your account security by asking you to confirm access withyour mobile phone, or a separate device. Thus if a hacker gets your password (by phishing, social engineering or as a result of a data leak) they cannot access your account because they do not have your phone. 

Note you MUST also activate FaceID and/or have a PIN on your phone. 

Here's how to activate 2 Step Verification in your Google Account: 

Go to myaccount.google.com and sign in

Select 'Security' on the left menu 

Under the 'Signing in to Google' box select > '2-Step Verification and follow the prompts. 

You can select a number of options:

1. If you are logged in with the gmail app on your phone already you will see it in the list. When you sign in on another device it will send a message to the gmail app and you push a button to approve access
2. Get an SMS - you can select to have a code sent to your phone when you login. 
3. Use an app such as Google Authenticator (App Store Google Play) or Authy - when you login you open this app to get a one time code to enter, it doesn't rely on an SMS so if you don't have service for some reason this is a great option. 
4. Use a hardware key - If you have a Yubikey or similar hardware USB security device, you can register this with your account

We highly recommend you enable more than one of these options, for example SMS + Google Authenticator