As Wikipedia puts it, “(Apostilling) is the legalization of a document for international use under the terms of the 1961 Hague Convention Abolishing the Requirement of Legalisation for Foreign Public Documents. Documents which have been notarized by a notary public, and certain other documents, and then certified with a conformant apostille are accepted for legal use in all the nations that have signed the Hague Convention.”
The best way to learn about this important process, is to read the basic information provided on the website apostilleinfo.com
Follow the links to your country, and your state.
This is only required for your criminal record check, not your other documents.
If you want to send a copy of your original university degree, you must get a color copy made, and then have it notarized and apostilled.
***Canada does not participate in this process, so you do not get your criminal check apostilled if youre Canadian. You must get it notarized, and then verified at the Korean consulate.