ArriveCAN

Before travelling to Canada, all persons without distinction — Canadian citizens, permanent residents and foreigners alike — must complete their travel and quarantine information on the ArriveCAN app, which can be downloaded from Google Play or the App Store, or completed online.

ArriveCAN App (Download or Complete Online)

Caution
Airlines will not board passengers who do not have an ArriveCAN reference number and border officers will not admit foreigners who have not completed the necessary information.

The official Government of Canada website link is here:
https://www.canada.ca/en/public-health/services/diseases/coronavirus-disease-covid-19/arrivecan.html

Tip on using the ArriveCAN app
Choose language in the menu (three bars, upper left) then follow the prompts. Most foreigners will choose ‘Essential Travel’ or ‘Voyage essentiel’) as the reason for the travel.

ArriveCAN Video
Use ArriveCAN to provide mandatory travel information (video) – Canada.ca

Supporting Documents Required by Airlines and Border Officers
Foreigners travelling to Canada must demonstrate that they are admissible as visitors, international students, temporary foreign workers, or as permanent residents. Airlines are legally obliged to check if a passenger has the necessary documentation from Immigration Canada before authorizing travel to Canada. Border officers will not admit a foreigner who is determined to be inadmissible.