Square is currently testing a food ordering service called Square Pickup. Square Pickup lets you order food ahead of time from a Square merchant and pick it up later.
The app is currently in beta for Android and iOS. Several San Francisco based restaurants are participating in the service. The menu of the restaurants are loaded in the app. You just have to pick what you want to eat and order it through the app.
From that point, you can pay with Square. There are thousands of merchants that have their menus loaded into Square accounts.