Two groups of family-based immigrant visa categories, immediate relatives and family preference, are provided under the provisions of United States immigration law, specifically the Immigration and Nationality Act (INA). You can learn more about these two categories of immigrant visas on usvisas.state.gov.
If the petition is filed with the U.S. Citizenship and Immigration Services (USCIS) in the United States, the case will be processed through the National Visa Center (NVC) in New Hampshire. To apply for an immediate relative or family preference immigrant visas, follow the steps on the Immigrant Visa Process on usvisas.state.gov. Once you have completed those steps, review the instructions given to you by the NVC, along with the information presented on this website, for further guidance and instructions.
In some cases, the petition may be filed directly with the USCIS Seoul Field Office in Korea. If the petition is approved by the USCIS Seoul Field Office in Korea, the Field Office will forward the approved petition to the Immigrant Visa Unit. In this case, the intending immigrant receives the Instruction Package via email from the Immigrant Visa Unit, with a list of the documents that must be presented at the immigrant visa interview. You can learn more about the details on Filing the Immigrant Visa Petition with the USCIS Seoul Field Office on www.ustraveldocs.com/kr.