This option will save you having to send to countries that you do not wish to deliver to. When purchasing and adding their delivery address the customer will only be able to choose countries you select to be in the drop down.
To choose which countries can purchase from your shop, please follow the steps below:
Log into your 123-reg e-commerce package.
Select Country Settings from the dropdown.
Click the Countries tab.
Under the heading Country there is a drop down bar, from there choose which countries you would like to be able to purchase from your shop.