Can you ship outside the USA? Yes! Depending on what shipping rates you are using this may need some adjusting. The embed estimated shipping rates work well within the US, but might be low outside the states. You could experiment with using the maximum estimate.
Or you can set up specific shipping zones for other countries with their own shipping rules.
If you use the live shipping rates they work well internationally. However be aware that some international shipping quotes can time out. For the customer this means they get an error message at checkout. To mitigate this you can set up Shopify backup rates. Learn more about backup rates in the Shopify Help Center, or customize backup rates in your Shopify Admin.