My girlfriend works in China, and I study here in Canada. I want to experience immigration or PNP immigration. Do you want to get married before emigrating or get married after emigrating?

I suggest you get married before you immigrate, so that your girlfriend can come with you when you apply for immigration. If you immigrate first, then you need to apply for your girlfriend's spouse reunion, which involves another application. So in terms of cost, time and material preparation, it is better to get married first.