I am working in the United States with an H-1B visa, and my wife is here on an H-4 visa. She just got a job last week and started working. What will happen now?
Unfortunately, your wife may--unless you yourself are in the process of applying for U.S. lawful permanent residence--have violated her immigration "status."
Let's start by assuming that you are not applying for a green card. Under these circumstances, dependent family members (a spouse or child under age 21) who have H-4 status are not authorized to work in the United States. Rather, they are permitted to remain in the U.S. for only as long as you maintain your H-1B status by working for your sponsoring employer as outlined in your employer's H-1B petition. Neither traditional nor self-employment is allowed for H-4 dependents.
If your wife is working for a company or organization, her employment might come to an end in one of two ways. One way could be through the I-9, Employment Eligibility Verification form, which all employers must keep on file for current employees. The employee has until the third day of employment to provide documents showing proof of authorization to work in the United States.
If your wife has been working fewer than three days, and if her employer is complying with the I-9 laws, she won't be able to provide any documents to show that she has work authorization. The employer then must terminate her employment.
The other way that her employment could come to an end is if the employer asks for her Social Security Number (SSN) with which to pay her. Only persons in the U.S. who have authorization to work can get a SSN. Therefore, when your wife's employer asks for her SSN, and she does not have one, that should alert the employer to inquire further into her work authorization status by reviewing the I-9 form. And again, if the employer is complying with the I-9 laws, it will discover the problem and terminate her.
Another problem your wife might have is that she will be ineligible to extend her H-4 status while staying here by submitting Form I-539. To be able to extend her stay from within the United States, she needs to have maintained lawful status. By working without authorization, she violated her status, so she does not meet this requirement.
The most likely solution to the above problems may be for your wife to stop working, travel outside the United States, and return with a valid H-4 visa. Once she returns, she again would be in lawful H-4 status, and also eligible to extend her stay. But before she does anything, it will be best for her to talk to an immigration attorney who can review her particular situation and advise her on the best course of action.
There is, however, another possibility to take into account: That you are in the process of applying for a U.S. green card. In that case, your wife would be eligible to work in the U.S. -- but only after obtaining a work permit from U.S. Citizenship and Immigration Services (USCIS). See H-4 Spouses: How to Apply for a Work Permit on Form I-765 for details on eligibility and how to apply.
Beware, however, that it can take a few months to obtain the work permit and that applying for and obtaining it will not "cure" any prior employment that was not authorized. As noted above, if your wife did work without authorization, her first step is to talk with an immigration attorney.