At the end of your immigrant visa interview, the consular officer will inform you whether your visa application is approved or denied.
Some visa applications require administrative processing, which takes additional time after the interview with a Consular Officer. The timing required for administrative processing varies considerably from case to case; therefore the Consular Officer will not be able to provide an estimate of how long this necessary process will take.
If your visa application was placed under necessary administrative processing and the Consular Officer also advised you to submit additional documents to complete your case, it is likely that the case will continue under administrative processing even after the requested documents have been submitted.
While the case is undergoing administrative processing, you will not be contacted by the Consular Section. Furthermore, the consular section will not be able to provide further information about the case until the administrative processing is completed.