How long does it take for a person being petitioned by a US Citizen to be able to work in the United States ? Person is here in the US.

I cannot answer that question completely without knowing how the person entered the US. However, assuming the person entered lawfully and is not limited in their ability to adjust status, the process involves fling the I-130 and I-485 with all required supporting forms and documents at the National Benefits Center in Chicago. The process is explained in detail at the USCIS website, which is www.uscis.gov. Once all forms and documents are properly received, the person will be fingerprinted. Some time after the fingerprint appointment, the applicant will receive the work permit. The time it takes to receive the initial work permit will depend on where the applicant lives, but generally it takes about 60 days to receive it.