Can wife abroad apply for H4 when husband is still on OPT?

Hi, I am on OPT and my H1B got recently approved. I want to bring my wife as soon as possible, ie. 10 days before October 1. It is possible for my wife to apply for H4 visa while I am still on OPT and do not have H1B stamping on my passport? If it is possible, is the process any different and any extra document needed?

She can go for H-4 stamping even prior to Oct 1 (but after July 1) and travel to US close to Oct 1. Your visa stamp is not a pre-requisite for this.