The entry document needed for visa-exempt foreign nationals travelling to Canada by air is the Electronic Travel Authorization.
In case if your air travel route contains a Canadian airport, then you may need to solicit an eTA. (You can apply for an application online, it’ll cost you only 7 CAD.) There are some exceptions to this. In order to be informed on the important information you may need, please go to the official online data given by the Government of Canada[1].
Please note: Passengers are entirely in charge of getting the travel documents needed for their trip.