How to Handle International Shipping
The plugin supports international fulfillment through FBA as long as your FBA policy allows it. You have to have the international export services active on your Amazon Seller and FBA account. However, you can also use the settings to turn OFF international fulfillment, and the plugin will not send orders to Amazon which have a destination address outside your home country as configured in the normal WooCommerce settings.
Note that using multiple Amazon regions and/or marketplaces at the same time is not supported. See this answer for more details.