An H-4 visa is a nonimmigrant (temporary) visa permitting a foreign national to enter the United States as the spouse or minor, unmarried child of someone who holds an H-1B, H-1C, H-2A, H-2B, or H-3 visa. (All of these categories are for temporary workers or trainees coming to the U.S. at the request of a U.S. employer.)
There are no limits on the number of H-4 visas given out each year.
The H-4 visa allows you to come to the U.S. to accompany the primary visa holder. Your rights are basically derived from that person. You will have the same authorized length of stay. If the primary visa holder fails to maintain his or her status, you too will lose your status. If that person obtains an extension of status, you too may extend your status. Of course, if you independently do something that violates your status, like work without authorization, your visa can be cancelled.
Like the primary visa holder, you will be allowed to travel in and out of the United States at will.
You may not accept employment in the United States unless you separately qualify for a work visa in your own right. You may, however, go to school in the U.S. without obtaining a separate visa. See, "Can You Work in the U.S. With an H-4 Visa?"
In order to qualify for an H-4 visa, you must:
In addition, as with all U.S. visas, you will need to prove that you are not "inadmissible" to the United States. The grounds of inadmissibility include things like having committed a crime, been a member of a terrorist group, or contracted a disease of public health significance.
First, your spouse or parent will need to receive a job offer or other qualifying offer from an employer in the United States. After the employer has taken any required preliminary steps, such as obtaining approval of a visa petition from U.S. Citizenship and Immigration Services (USCIS), you will need to assemble or prepare the following and go to a U.S. consulate in your home country to apply for the H-4 visa:
H-4 costs to the individual applicant include a nonrefundable application processing fee and possibly a reciprocity fee upon visa issuance, depending on which country you are from. See the State Department “Fees for Visa Services” page for the latest amounts.