You can add additional target countries to your product data source to show your products to multiple countries. Use this option if you expect your products to remain the same for multiple countries and you don't want to create a separate product data source.
You can view and edit the target countries of your product data source from the 'Data sources' tab. You can find the 'Data sources' tab via the Settings and tools icon in the top right of Merchant Center or, under 'Your business', go to the Products tab and select View data sources.
Instructions
In your Merchant Center account, click on the Settings and tools icon
.
Select Data sources.
Under the 'Product sources' tab, click on the 3-dot menu icon
In the 'Add more countries' box, select additional target countries.
Click Save.
To remove a country, de-select the country in the 'Add more countries' box and click Save. If you need to exclude a country from specific products in your product data source, you can use the excluded countries for Shopping ads [shopping_ads_excluded_country] attribute.