Work permit is normally called as Employment Authorization Document (EAD). EAD is needed if you are not a citizen or legal permanent resident, to prove that you may work in the United States.
Categories
USCIS issues Employment Authorization Documents (EAD) in the following categories:
•EAD: This document proves you are allowed to work in the United States.
•Renewal EAD: You should apply for a renewal EAD six months before your original EAD expires.
•Replacement EAD: This document replaces a lost, stolen, or mutilated EAD. A replacement EAD also replaces an EAD that was issued with incorrect information, such as a misspelled name.
•Interim EAD: If USCIS does not approve or deny your EAD application within 90 days (within 30 days for an asylum applicant; note: asylum applicants are eligible to file for EADs only after waiting 150 days from the date they filed their properly completed original asylum applications), you may request an interim EAD document.
People Needing EAD
The specific categories that require an Employment Authorization Document include (but are not limited to) asylees and asylum seekers; refugees; students seeking particular types of employment; applicants to adjust to permanent residence status; people in or applying for temporary protected status; fiances of American citizens; and dependents of foreign government officials.
Application
You may be eligible to file Form I-765 electronically. If you are not eligible for electronic filing, you must file an Form I-765 (Application for Employment Authorization) by mail with the USCIS Regional Service Center that serves the area where you live. Please read the entire application carefully and submit the right documents, photos, and fee.
If USCIS does not approve or deny your Employment Authorization Document application within 90 days (within 30 days for an asylum applicant; note: asylum applicants are eligible to file for EADs only after waiting 150 days from the date they filed their properly completed original asylum applications), you may request an interim Employment Authorization Document. You must go to your local USCIS office and bring with you proof of your identity and any documents that USCIS has sent you about your employment authorization application.