The Edmonton, AB office is where most of the applications are processed. I am not sure if they delegate grunt work in other visa offices and then do the final issuing in Edmonton but if your application is online, that is most likely where you will get processed. I am assuming that since most visa offices will be understaffed and therefore busy with their paper applications, most online application will be handled by the Edmonton office.
Before COVID, they would be spread out, I have heard one person applying from India and getting it approved from Australia.