Ad extensions

A feature that displays extra business information with your ad such as an address, phone number, more webpage links, or a coupon.

Most ad extensions allow you to add your additional business information to a basic text ad. Some examples of ad extensions include offer extensions (adds a printable coupon to your ad for use offline) and ad sitelinks (adds additional webpage links).
Ad extensions are particularly useful for accomplishing specific business goals. For example, if you're a local business or a business with multiple store fronts, you might want to encourage people to visit or call your physical store. One way to do this is by using location extensions, which allow you to include address information with your ad.
Ad extensions function differently depending on the type, and provide different reporting information based on how people on the web can interact with them. For example, call extensions provides information about how many times a person clicked your ad to call your business.