In my experience, it all depends on what you bought, who you bought it from, how much you paid for it, whether it had free shipping, and where you live. It simply isn't true that there is one answer for everyone. And it certainly isn't like buying from Amazon or KBC Tools (just to pick two extremes - Free & $$$).
I think I can safely say that the majority of your ALI shipments will probably get delivered by Canada Post. Most Ali vendors are aware of the fact that Canada has a postal agreement with China. This agreement makes their shipping costs much lower than the actual cost - this has been discussed at length elsewhere on this forum. For most low cost shipments this has worked well for me. I often don't even have to pay HST. But that isn't true for more costly stuff that has to go through customs where it gets opened, rummaged through, often damaged, and sometimes lost - all for a nasty fee which you will have to pay in addition to your purchase cost or you don't get your item.
Something you need to know is that Ali isn't one big vendor for thousands of vendors like Amazon. Instead, it's more like an umbrella group where each vendor is free to do their own thing. Yes, Ali has rules for them but not nearly so controlled and strict as Amazon. Each vendor on Ali is very different and very independent. If you find an Ali vendor you like, try to stick with them. Doing so will provide a "LITTLE" more shipping certainty than hopping around will.
If your vendor chooses a non-national carrier all bets are off. This can be everything from one of the majors (UPS, FedEx, etc) to a slow boat passing through every 3rd world country on earth several times..... Free shipping is sometimes this last version. But even expensive shipping can be this last version.
If you have not guessed, shipping certainty isn't one of Ali's strengths. Throw a bag of dice in the air and pray. With some grovelling and a few sacrifices to the shipping God's you might get lucky!
To be very honest, shipping is one HUGE reason I like Amazon. Shipping is often a major decision factor for me.