UPDATED: The White House has proposed a significant change that would allow H-4 visa holders to work while in the United States. Read more about this proposal here.
How does an individual with an H-1B visa bring their immediate family members with them to the United States?
With an H-4 visa. To obtain an H-4 visa you must either be the spouse of the H-1B holder or a dependent under the age of 21.
The video below gives an overview of that you need to obtain an H-4 visa and what you can and can not do while living in the United States. You can also read our article What can you do in the United States with an H-4 visa? for more information on the H-4 visa.