It's no trouble to exchange dollars in Canada. Almost all shopping malls and banks in big cities have dollar/Canadian dollar exchange offices (fees). The price difference changes every day. You can Baidu yourself.
In cities near the United States in Canada, many shops charge in US dollars. Honesty will charge according to the proportion of the day, and small vendors will charge one-on-one (lose money in US dollars).
Many students who come to the United States and Canada use their parents' credit cards at home, and their parents pay in RMB at home.
After you arrive in Canada, you can't use a check until you open an account in the bank. These are not difficult. When you come to Canada, you will know how to use them at a glance.