No, you opt-in to shipping internationally.
Please note that this is a preference, not a guarantee.
If there are not enough people signed up in your country, you may get matched internationally, despite your preference. Likewise, if you opted-in to international shipping, you may be matched domestically.
Please see this helpful post for some international shipping advice.
We do allow drop shipping in the exchanges so please be aware that signing up for an international exchange does not guarantee you will receive a gift from another country, even if you are matched internationally.