You must file an application with the US citizenship and immigration department if you want to extend your visa for a longer stay in the US. This can be done by filing form I-539.
You should make your application at least 45 days in advance from the date your visa would expire.. You can find this date in the lower right-hand corner of your I-94 form that you received when you enter the country.
Am I eligible two extend in my visa? The answer would be yes if you have lawfully entered the United States.If your visa remains valid. You have not committed any crimes while in the country. . If you have not violated the conditions of your admission. Your passport is valid. During the duration of your stay. For more information you may go to the US citizenship and immigration web site