Regardless of the length of your stay in Canada, passengers travelling to Canada will need an EVA or visa.
Travellers to and from the United States with a stopover in Canada, as well as participants in visa-free transit programmes, do not need an EVA or visa to transit Canada.
You may be able to transit through Canada without a Canadian visa if you are from China and your final destination is the United States. There is now a visa-free transit programme for Chinese nationals. All travellers must present a valid visa for the United States and a valid passport issued by the People's Republic of China. It is also essential to travel via clearly defined airports in Canada. In this case, you will need to apply for a transit visa. You can find out more from https://www.canada.ca/fr/immigration-refugies-citoyennete/organisation/publications-guides/bulletins-guides-operationnels/residents-temporaires/visiteurs/programme-transit-chinois.html
In short, a AVE will usually be requiredTo find out more, depending on your nationality.
An agency service 