Failure to depart the United States on time will result in being out of status. Under U.S. law, visas of individuals who are out of status are automatically voided (Section 222(g) of the Immigration and Nationality Act). Any multiple entry visa that was voided due to being out of status will not be valid for future entries into the United States.
Each country has its own visa application requirements. Make sure to check with your destination country’s appropriate government website to find out. Requirements typically include filling out the visa application form, providing your passport for stamping if required, a photograph, and additional documents such as your flight itinerary, hotel booking or letter of invitation.
The Democratic People's Republic of Korea (North Korea) requires that its citizens obtain an exit visa stating the traveller's destination country and time to be spent abroad before leaving the country. Additionally, North Korean authorities also require North Korean citizens obtain a re-entry visa from a North Korean embassy or North Korean mission abroad before being allowed back into North Korea.