Adding a country selector
If you add a country selector to your theme, then your customers can choose their country or region from a dropdown list of of countries and regions that you've added in your Shopify Payments settings. The local currency is also displayed in the dropdown list beside each country or region.
The Geolocation app by Shopify makes country and language recommendations to your customers based on their geographic location, and browser or device language. With the Geolocation app, you also have the option to add a selector in the footer of your online store that lets your customers to choose their country and language.
You can set the default country or region for your international buyers by using international domains. For example, you can use
your-shop-name.com in the United States, where your online store appears in English and prices appear in USD. In France, you can use
fr.your-shop-name.com, where your online store appears in French and prices appear in EUR. You can use the Geolocation app along with international domains when selling in multiple currencies. The Geolocation app lets customers to change their location manually if they're on the wrong domain.
Edit your theme code to add a country selector
If you want to edit your theme code so that customers can choose their country or region, then you can use Shopify Liquid to create country selectors in your storefront. This is an advanced tutorial. Edit your theme code only if you have coding experience. Alternatively, you can hire a Shopify Expert.