The partnership currently only covers KFC restaurants located in the San Francisco Bay Area, Los Angeles (that's me!), and Orange County but with plans to expand to other cities in the coming months.
DoorDash is an on-demand restaurant delivery service that also partnered with Taco Bell earlier this summer. KFC and Taco Bell are both brands that fall under the Yum Brands umbrella (so is Pizza Hut). The service touts "fast delivery within an hour" with no minimum order size.
You can access the service by either downloading the DoorDash app for iOS or Android, or by visiting www.doordash.com.