USCIS allows immediate family members of H visa holders (H-1A, H-1B, H-2A, H-2B, or H-3) to get H-4 visas to lawfully come and stay in the US. These visas are usually issued at the local US consulate office abroad. However, if the person is already in US, he or she can obtain H-4 status by filing Form I-539 for change of status.
H-4 visa holders are not eligible to get a Social Security Number and cannot be employed, but they can hold a driver's license, open bank accounts, and get an Individual Taxpayer Identification Number for US tax purposes.
Family members may alternatively be admitted in other non-immigrant categories for which they qualify, such as the F-1 category for children or spouses who will be students or the H-1B category for a spouse whose employer has also obtained approval of an H-1B visa petition to employ the spouse. An H-4 visa holder is admitted to the US for the duration of the primary (H-1B, H-2A, H-2B, or H-3) visa validity.
Since H-4 visa holders are not issued a social security number, an ITIN (Individual tax identification number) should be obtained before filing for joint tax returns by filing Form W-7. They are not authorized to work in the United States, though they are allowed to study.
Obama administration officials unveiled proposed rules today that would allow spouses of some H1-B visa holders to work in the U.S., along with other changes designed to encourage highly skilled immigrants to stay here. 
- Vasic, Ivan (2008). The Immigration Handbook: A Practical Guide to United States Visas, Permanent Residency and Citizenship. McFarland. p. 93. ISBN 978-0-7864-4009-2.
- "Application To Extend/Change Nonimmigrant Status". USCIS. Retrieved 9 August 2010.