Since it's 2:30 PM Eastern on Sunday, I assume you are already enjoying Canada.
I drive to Canada all the time from the U.S. and I do not have a "Canadian" Insurance card. There is no need for one.
However;
Some Fleet Cars (Company Cars) do require this. Not sure if you are driving a company car or not.

I hope you enjoyed Canada. I've made that particular crossing many times. There is a lot to see around the Niagara Falls area on the Canadian side.
I'd send you a list but I am sure it's too late. Have fun.