The immigration laws support and promote reunion of families. That is, if you have a family member who’s a resident (green card holder) of the United States, you can immigrate to USA and avail yourself of all the advantages of being a citizen. In order to be qualified for filing such a petition, you need to be either the spouse or unmarried child of the permanent resident.
Once you make sure that you are eligible, you can either acquire your permanent residence while inside the country, through the adjustment of status or apply abroad in the consulate. Under this, your family member should file a petition I -130, on your behalf stating your relation. It then has to be approved by the USCIS for further processing.
You can also apply for permanent residence while being outside the country through the consular process, while being outside the country. In this case, the US consulate handles your visa issue and decides your qualifications and eligibility.
Another way to obtain permanent status in the United States is that you are an immediate relative spouse, child, or parent is a US citizen. Issue of these visas is preferred to other categories and thus they are processed immediately. That is, when your sponsor or beneficiary is petitioning I-130, you can apply for I-485. Even if you are not an immediate relative, you can be a family member to a US citizen and still avail yourself of the advantages of this category.
A special circumstance can also entitle you to a petition for permanent residence through family. These include children born in US to foreign diplomats, widows and a few more.
Unmarried child to a US citizen, spouse and minors to permanent residents, married children of US citizen are issued visas right away. In case of death of the family who’s your sponsor, your petition will be abandoned. Your sponsor is legally responsible for your financial dependence. To accept this responsibility, an affidavit of support I -864 is essential to be filed.
Even after approval, you have to pass the visa eligibility, which needs you to be a physically and mentally fit person without having a criminal record.