Create a new content page where you will place the google verification code.  This code can be obtained directly from instructions provided by Google.

Call the page "Google Verification" and switch the How do you want to build this page? to Use HTML Editor.  

In the HTML editor copy and paste the HTML provided by Google.  Typically something like this:
​google-site-verification: googleABCDEFGHIJKLMNOhtml

Now that your page is saved, you need to generate a vanity URL to route the visit to this page.  

Go to the Company Menu and click on Setup Vanity URL.

Enter the / followed by the HTML page for the Vanity URL

Select Content and then find the Google Verification page you just created.

Google can now find this page.