You will often hear these called Forwarding Numbers, Call Extensions, Ad Extensions or Call Conversions. These are ultimately one of the same and within Google let you report on the calls that you receive through call extensions and call-only ads, offering details such as call duration, call start and end time, caller area code and whether the call was connected. You can count phone calls of a specified duration as conversions, and use automated bidding strategies to increase the likelihood of conversions.
When you use a Google Call Extension, Google will assign a phone number to your ad (or Infinity number if you set this up). This phone number, will show with your ad on tablets, laptops and desktop computers. A clickable “Call” button will be displayed with your ad on high-end mobile devices (such as iPhones and Android devices with full Internet browsers). This allows for fast execution for callers being able to reach your business via Google without having to click through to your website. The same cost per click applies to the "Call" button.
Yes, using an Infinity number in place of a Google number will mean you can track calls made directly from this ad in your Infinity Portal. You simply setup an Infinity fixed number and place within your Google Call Extension field after finding the section to “Show my ad with,” and selecting My own phone number (don’t use call reporting).
Using an Infinity number instead of a Google forwarding number will allow you to have full visibility of calls from the ads directly alongside your other Infinity data. We strongly recommend that you always use the exact Campaign naming convention when setting up the fixed number so that it filters into the correct Campaign within the Infinity Portal.