I-130 is processed and approved in the US. Then it moves to National Visa Center in preparation for transfer to a US consulate abroad where final paperwork is completed and interview is held.
Sponsor needs to provide proof of US citizenship and proof of relationship (sponsor's birth certificate with parents names listed) when I-130 is filed. After I-130 is approved and the processing moves abroad, parents need to provide birth certificate and marriage certificate. If these are not available for some reason, then letter from relevant government entity is needed for non availability. This letter should be supplemented with two affidavits from close relatives who are aware of the birth/marriage.
An affidavit of support I-864 is also needed before processing moves abroad. NVC will request it from the sponsor.
There are fees involved at various stages.
