Checkout Settings
To edit the checkout settings for your shopping cart click on Settings
on the admin menu and click the Checkout link.
Checkout Message: If you want a message on your checkout page
you can enter it here.
Checkout Options
There are extra fields that can be shown on the checkout page for
your customers to fill out.
Countries
Here you can select what countries you want listed in the billing and
delivery country dropdowns on the checkout page.
CMS Help - Checkout Settings