When a visitor arrives in the United States, they are given a date that their visa is valid until. This date is generally notated on your arrival stamp, or I-94. If you want to stay longer than the allotted time, in order to avoid being barred from future visits, you need to apply for a Visa Extension with U.S. Citizenship and Immigration Services (USCIS).
Individuals who need to extend their stay must submit Form I-539, Application To Extend/Change Nonimmigrant Status. You can apply for the visa extension after 3 months of arrival and it should be at least 45 days before the authorized date expires according to USCIS processing times. The USCIS will evaluate your situation to issue an approval or denial letter. Form I-539 is only applicable to certain nonimmigrants who came to the U.S. legally and remain in legal status without violating any admission conditions.
Please note: RapidVisa does not assist with visa extensions.