If you have a Google+ page, you can link it to your AdWords campaigns to show Google+ endorsements in your ads. This feature can help your ads stand out, increase credibility if you have a strong Google+ presence, and can help improve CTR.
You need to have a Google+ page. This page and your website need to be linked in order to prove that the Google+ page belongs to you. You can link your Google+ page and your website by adding your website's URL to your Google+ page. You will also need to add your Google+ URL to your website.
To set up social extensions, follow these steps: