Dear Harsh Kumar ji,
I think, since the accident report is now introduced online in the portal, there is no need to submit it to Branch office in physical form. But in given case, the queriest can submit the physical prescribed form of accident report to the Branch office without insurance number. Still I prefer to enroll the person as IP first and submit the accident report online. This will not take much time. Only thing, one need to have basic details of the person to whom he is going to enroll.