The Hague Convention on the Service Abroad of Judicial and Extrajudicial Documents in Civil or Commercial Matters allows for the service of judicial process from one participating country to another without use of diplomatic channels. Document requests from one party to another party to the Hague Covention must follow its protocols. There are only 68 countries which have adopted the Hague Convention, but these include so many of the world's big countries, and 'First World' countries, that it's interesting to note which nations from these two categories are not parties to it.
Think of these as the 'TABS' countries. It may be unlikely that case will come up involving parties from countries other than these which have not signed the Hague Convention.
Austria is the only country in Europe which has not signed on.
Only about half of the Southern American natons are participants with Brazil and Chile being notable exceptions.
Of the BRICS emerging economies, South Africa, along with Brazil is also not covered by Hague.
Indonesia, Malaysia, and the entire Indochina Peninsula are not covered. Turkey, Israel, Kuwait, Pakistan and Egypt are the only Middle Eastern participants.
Two other countries with advanced economies, New Zealand and Taiwan, have not signed onto the Hague Convention.
The USA, Canada, Mexico, Russia, China, Japan, India, and Australia have all signed the Convention. So if you think of those big countries, and Europe minus Austria, you'll be able to remember who's covered by Hague.