If looking for rentals most are not done through real estate companies. Either listings are posted on websites like Craigslist or Kijiji or large rental property companies have their own applications systems. Beware of scams and in general you should expect to only be able to rent once you get to Canada. Most landlords want to meet people in Canada before renting to them and to protect yourself you’ll want to look at the rental and see the neighbourhood first. You also are much more likely to be scammed if trying to rent from abroad.