Under U.S. immigration laws, only certain immigrants are allowed to work, usually after they apply for a work permit called an Employment Authorization Document (or EAD). Some years ago, asylum applicants were allowed to get an EAD as soon as they'd submitted their application for asylum and work while their case was being considered, but no longer.
Now, in order to be granted a work permit, you have to either
If you win your asylum case, you not only gain the right to work in the U.S., but don't need to apply for an EAD with which to do so. Your asylum grant allows you to obtain an unrestricted Social Security card, which is all you need to present to an employer.
Now let's look at some unique issues raised by the second option, of applying for a work permit if there's been no decision on your case within 150 days of your application. Given that long waits are a common part of every type of immigration application, especially asylum applications in recent years, you can count on 150 days passing without any decision on your asylum application if you filed it with an asylum office of U.S. Citizenship and Immigration Services (USCIS). Likewise, if you are in removal (deportation) proceedings in immigration court and want to apply for asylum, you could easily be waiting more than 150 days for a court date to see an immigration judge.
You will want to start the asylum application process as soon as possible, so the clock can start running. If you're applying with USCIS, you'll get a receipt notice telling you when it received your application, which will be the date the clock starts. If you're in removal proceedings, fortunately you don't have to be in front of an immigration judge to get the process started. You can just go to the court and "lodge" (give to the court) your asylum application. The court will stamp your copy of the application with a notation that it has been lodged, so that when you apply for your EAD you can prove to USCIS that the clock started that day. (You still have to officially "file" your asylum application with the court when the judge tells you to.)
Your wait to apply could be even longer than 150 days. Various things can occur to "stop the clock" (stop the counting up of the 150 days). For example, if you request more time or fail to show up for a fingerprinting appointment, the government will stop the clock during this time. If USCIS requests more evidence from you in order to be able to make its decision, the clock will stop until it receives your response. If you're in removal proceedings, the clock will stop if you ask for your case to be postponed so you can get an attorney; if you ask for more time to prepare your case; if you say no when the judge asks you if you want your asylum claim to be heard sooner than normal; or if you file a motion that delays your case. Applicants in removal proceedings can track the progress of their "asylum clock" by calling the Executive Office for Immigration Review (EOIR)'s immigration case status information number, 800-898-7180.
Various problems with the 150-day clock process have been observed, too. In many cases, the clock got stopped without the applicant even knowing or hearing about it, perhaps based on a government mistake. Applicants then found it very hard to get the clock started up again. This led to a court settlement, which enabled a more open asylum-clock process. To learn more, see Nolo's legal update Asylum Applicants Seeking Work Permits: New Settlement Terms.
Once 150 days have passed and you have applied, the government has 30 days to give you (or deny) your EAD.
If 150 days pass with no initial decision on your asylum application, you'll need to take steps to apply for a work permit.
The application process involves filling out USCIS Form I-765. For more detailed instructions on how to complete this form as an asylum applicant, see How to Apply for a Work Permit as an Asylum Applicant.
For in-depth information on asylum and refugee protections and all key immigration law issues, see U.S. Immigration Made Easy by Ilona Bray (Nolo).