Hi I'm so sorry if this is not in the correct spot..
I've been getting mixed advice but I believe that I must wait for the welcome letter to arrive from the NVC which includes the invoice ID number.. Also I've been told I'm wrong about this, but I've read on the NVC site that this visa is immigrant visa and that it must be treated as such when navigating the NVC / ceac sites.. I was told I'm wrong that I have to use non immigrant and start the ds160 and pay the fee and schedule his interview.... I'm so confused now. We've been "ready" status since Thursday last week.. Any advice would be great! Thanks so much 🙏