Certain exchange visitors (J-1) are subject to a two-year home-country physical presence requirement which requires you to return to your home country for at least two years at the end of your exchange visitor program. This is also known as the foreign residence requirement under U.S. law, Immigration and Nationality Act, section 212(e). If you are unable to return to your home country to fulfill the two-year requirement, you must obtain a waiver approved by the Department of Homeland Security prior to changing status in the U.S. or being issued a visa in certain categories for travel to the U.S.
Reference: US Department Of Sate (https://travel.state.gov/visa/temp/info/info_1296.html)
For information on coming to the United States for temporary or permanent employment,