People travelling from countries that are not eligible for visa-free travel to the United States under the VWP ( Visa Waiver Program) require a permit to enter the USA. The visa comes in the form of a stamp in your passport. The validity, however, depends on the officer issuing the permit. Based on your profile, this can vary from 6 months to a maximum of 10 years. They are of two types – Immigration, and Non-Immigration Visa. Since the latter involves permanent residency visas and most US Visa application from India involve temporary stay, through this guide, the Non-Immigrant Visa (NIV) will be discussed.