Google Ads accounts only
A callout extension is informational text, such as products, services, and promotions that the site offers, that can be displayed with a text ad. The ad network may show between two and four callouts with an ad.
You create shared callout text and settings, including dates during which the callouts can appear with ads, at the account level.
The Extensions > Callout library in Campaigns > Campaigns lists all of your account-level callouts, and you can create and manage your shared callouts there. See the ad network help for the maximum number of ad extensions per Google Ads account.
Callouts in your library aren’t used with your ads until you assign them to a campaign or ad group. From the Extensions > Associations view, you can assign any of your callouts as possible extensions to all ads at the campaign level or ad group level. You must assign at least two callouts per campaign or ad group for your ads to be eligible to appear with callouts. Callouts at the ad group level override callouts at the campaign level.
Search, Social, & Commerce maps the clicks on an ad extension and the resulting conversion to the keyword associated with the ad in which the extension is included. No cost or click data at the extension level is available in Search, Social, & Commerce.
In Google Ads, you can see cost and click data on the Campaigns tab > Ad Extensions tab.