how long will stay in NVC to get the visa after submiting all the docments required by NVC ?

Answer 1

By experience, the docs may stay in NVC for a number of weeks while your local US Embassy schedules an interview date for the beneficiary. Once the date is set, NVC will ship the docs to the Embassy.

In my in-laws case, the docs sat in NVC for around three months until the embassy in Manila scheduled the interview. The visa arrived 4-6 weeks after the successful interview.