72-hr visa free transit

I have two questions:
I am Canadian citizen. Flying from Canada to Shanghai (staying less than 72 hrs) to Hong Kong. As I do not know if Hong Kong is consider a separate country/region. Am I eligible for the 72-hr free transit in my stay in Shanghai?

I asked Air Canada (airline which I am flying on) however they do not know where to apply for this. Where do I need to apply for this 72 hr free transit? Thank you