Can I invite my friends to apply for a permanent residence visa in Korea?

You can't. After the revision of the Implementation Order of the Exit-Entry Administration Law of South Korea, overseas compatriots who have the qualifications to acquire nationality and permanent residence can also invite their relatives to apply for employment visit (H-2) visas, just like nationals (including those who have newly acquired nationality). Relatives are not friends, so they can't. Korean immigrants generally refer to obtaining permanent residency in South Korea. In fact, South Korea's green card and South Korea's permanent residency are the same concept. You can immigrate to Korea with the right of permanent residence, which is also commonly known as the green card. It is called green card, because the document of permanent residence in the United States is green, so China people are used to calling permanent residence abroad a green card.