how to submit civil documents and photo for IV

老師們，剛剛網上遞交了給在中國的媽媽的Immigrant Visa and Alien Registration Application. 然後 confirmation page 要求1. Obtain and submit required supporting civil documents.

2. Obtain and submit photographs that meet the department of state's visa requirements. 3. review the information specific to U.S. Embassy general where your visa interview will occur.

有點吃驚，材料和照片不是應該麵試時帶到廣州領館的嗎？難道該寄到NVC？我先前已選過所有材料用電子文檔發送，那麽是否該掃描並email 到NVC?

拜謝！！