Your valid passport that along with visa in valid or expired passport as well as your customs declaration form which your receive and fill in the flight. If you are a visa exempt then only valid passport and declaration form.
You may also be asked to show proof of your purpose of visit depending on what visa you applied for or what you declare as purpose of visit to Canada.
As a visitor you will have to provide address of place where you will be staying along with names of people you are visiting, if asked.
As a student you need to have proof of acceptance or enrolment and possibly accommodation, if asked.
Any statement you provide is subject to verification by officer at inspection in order to determine you admissinabiliy to Canada.
My mom doesn't speak good English.. So when she came here as a visitor, this is what I told her..
Please prepare all the documents that the Canadian Embassy have returned to you when you applied.. I trained her how to answer questions..When she arrives, she just presented everything to the Immigration Officer..
The only had 2 questions for her:
1. Is this your first time in Canada? My mom answered, yes..
2. Is this your first time outside your country? My mom answered, yes..