H1B visa holders are allowed to bring their immediate family members (spouse and children under 21) to the United States under the H4 Visa category as dependents.
An H4 Visa holder may remain in the U.S. as long as the H1B visa holder remains in legal status.
An H4 visa holder is not eligible to work in the U.S. and is not eligible for a Social Security number (SSN).
An H4 Visa holder may attend school, obtain a driver's license and open a bank account while in the US.
H4 Visa holders can change / transfer to H1B visa status to work in the USA - if they qualify for sponsorship employment in accordance with the H1B visa requirements
To transfer from H4 to H1B requires obtaining an H1B Job / Visa sponsorship position - for details Click Here
Some recent state regulations prohibit H4 visa holders from obtaining a driver's license in cases where driver's licenses are no longer being issued on Individual Taxpayer Identification Numbers alone and an SSN is required.
The H4 visa is issued by the U.S. Citizenship and Immigration Services (USCIS) to immediate family members (spouse and children under 21 years of age) of the H1B visa holders.
USCIS allows immediate family members of H visa holders (H1A, H1B, H2A, H2B, or H3) to get H4 visas to lawfully come and stay in the US. These visas are usually issued at the local US consulate office abroad. However, if you are already in US, you can obtain H-4 visa by filing Form I-539 for change of status.
H4 visa holders are not allowed employment in US and are not eligible to get a Social Security Number and cannot be employed, but can hold a driver's license, open bank account(s) and get ITIN for IRS Tax purpose.
Family members may alternatively be admitted in other nonimmigrant categories for which they qualify, such as the F1 category for children or spouses who will be students or the H1B category for a spouse whose employer has also obtained approval of an H1B visa petition to employ the spouse. An H4 visa holder is admitted to the U.S. for the duration of the primary (H1B, H2A, H2B, or H3) visa validity.
Since H4 visa holders are not issued a Social security number, an ITIN (Individual tax identification number) should be obtained before filing for joint tax returns. There is a form called w-7 that needs to be filled and related documentations which is mentioned in the w-7 form must be notarized and to be sent to the address mentioned in the w-7 form.