You have to also submit all the necessary forms and supporting documentation to the National Visa Center after you pay the IV fees in order for the case to be complete and for the interview to be schedule. How long it will take to schedule the interview will depend on how soon you submit all the documentation and whether it is complete. Please let me know if you have any additional questions or how I can be of further assistance to you in this matter.
Answer Applies to: California
After you pay the visa fees, you must print the document cover sheets, and submit all of her documents to the NVC. The NVC will review the file, and when the file is complete, the NVC will contact the Embassy/Consulate to schedule your wife's appointment for her immigrant visa. In my experience, it typically takes the NVC 4 - 6 weeks to review the documents submitted. The NVC often requests additional documents, which can delay the scheduling of your wife's appointment. Therefore, it is impossible to give you a certain time frame within which the interview will be scheduled. It depends on how long it takes you to submit her documents, and then how quickly the NVC can schedule an appointment with the Embassy/Consulate.
Answer Applies to: Minnesota