To immigrate as the widow(er) of a citizen, you must prove the following: 1. you were legally married to the citizen, 2. you entered the marriage in good faith, and not solely to obtain an immigration benefit.
You may be eligible to receive a green card through widow/widower status if you: 1. Were married to a U.S. citizen at the time he or she passed away 2. Either have a pending or approved Form I-130 or you have filed a Form I-360 within 2 years of your spouse’s death (or no later than October 28, 2011, if your citizen spouse died before October 28, 2009, and you were married less than 2 years). 3. Are not remarried 4. Were not divorced or legally separated from your spouse at the time he or she died 5. Are able to prove that you were in a bona fide marital relationship until the time of your spouse’s death 6. Are admissible to the United States
Depending on whether an I-130 was submitted on your behalf, you will either do nothing (as the I-130 will be automatically converted to an I-360), or you will submit Form I-360, Petition for Amerasian, Widow(er), or Special Immigrant.
Generally, when you have a pending Form I-485, it is possible for you to apply for authorization to work in the United States. You must file Form I-765 concurrently with your Form I-485 and await the processing of your work permit.