Express Checkout functionality allows a shopper to order many items while just hitting the add to cart button once. Items are listed and a quantity box is shown next to each item. There is only one add to cart button at the bottom of the item listing. The shopper can indicate which items to order by setting the correct quantity for each item and hitting add to cart.
Items with attribute choices are shown with each individual selection as its own item to be added to the cart in express ordering mode. For instance, a shirt with sizes small and medium and colors blue and red would be shown as four lines, shirt small blue, shirt small red, shirt medium blue and shirt medium red. This method of ordering is useful for stores where customers generally order large numbers of different items and allows the user to make purchases without having to constantly go back and forth from the cart to shopping.
To activate express ordering for a particular department in your store go to the department edit screen for the associated department and check the box labelled express ordering under the options heading. If you do not see the express ordering checkbox it can be enabled from the settings area.
To change the layout for the items in express ordering mode go to inventory–>items–>layout and choose the express ordering tab.
Alternatively express checkout mode can be activated on a particular item page temporarily by using the querystring ?EO=1.
Sample URL with express ordering added manually