If you are on a J-1 visa you may be subject to the two year home requirement. If you are before you can get a immigrant visa you have to either complete that requirement or have it waived. You may be able to get what is known as a J-waiver which waives this home requirement. The two year home rule is also referred to as the foreign residence requirement under the U.S. Immigration and Nationality Act Section 212(e), or just INA s. 212(e).
The J-1 visa is a great way to travel to the United States and learn about daily life in America. It is a non-immigrant visa and was designed to foster global understanding through cross-cultural exchange. The program generally involves letting an American organization sponsor a foreign national who then works or studies in the United States for a short term and upon completion of the program then returns home. A prospective exchange visitor would need to first obtain a form called a DS-2019 from a sponsor in order to apply for the J1 visa. Here is a list of sponsors.