How do I get my degree and background check apostilled for my Korean visa application?

An apostille is an international certification that makes a public document valid abroad, used between countries in the Hague Apostille Convention. For a Korean visa, foreign documents (your degree and criminal background check) must be apostilled in the country that issued them, not in Korea, by that country's designated authority, and if your country isn't in the convention you get consular legalization at the Korean embassy there instead. Do this before you come, since it takes anywhere from a few days to a few weeks depending on the country. Some documents also need a certified Korean or English translation, so check the exact list on HiKorea for your visa type.