>> 1. For sending them email to priotrize, i just need to send letter of support.? or do i need the phac approval letter as well.?
if you dont have PHAC you can try just with " doctors note regarding due date". if you are getting the "letter of support for PHAC" too from doctor you need to upload that form for approval in
https://border-frontiere.powerappsportals.com/en-US/ . PHAC will get approved only when you upload the "letter of support" to
https://border-frontiere.powerappsportals.com/en-US/
>> 2.. After getting letter of support signed from my doctor, and to get approval from phac, i have to submit here
https://border-frontiere.powerappsportals.com/en-US/.?
yes. that is correct.
>> 3.After submitting here , are they replying on their own, or do i have to contact them again.?
while applying for PHAC they will ask if you need a VISA. at that time you have to give the UCI number. Once PHAC is approved visa decision will come faster if you have given UCI number. Emailing them after PHAC approval is not required but there is nothing wrong in doing that. I did that in my case.