To access these settings, go to "Edit promotions" from the Home page, then click the "Edit" button for the promotion you want to edit.
In the "Edit promotion" screen, open the tab "Discount rule".
By default promotions are available to all visitors, regardless of which country they access your store from.
Include or exclude
To restrict your promotion to a set of countries choose "Only visitors from the following countries" or "All visitors excluding those from the following countries" and select one or more countries from the list.