I'm not sure if you're asking how....they send you the request. But it seems only people who are notifying them via web form are getting the passport requests. That request tells you what you need to send and the address to send it to. For us we sent with DHL. It took two days to arrive. To make it easy I used UPS to have their passports sent to me in Canada.idk but thats suspicious.
Just send an email to Mexico to know what's remaining after medical approved and Decision made
If we need to send her passport and how... where and so on.