Citizens wishing to visit Canada must obtain a visitor visa issued by one of the Canadian diplomatic missions unless they hold a valid passport issued by one of the EU countries, Australia or New Zealand. From 2016, visa-exempt countries (except for the US) must apply for an Electronic Travel Authorization (eTA) when arriving to Canada by air. However, travelers don't need an eTA if traveling to Canada by land or sea.
Generally, you can submit your application online but for some countries, after the online application, fingerprints and photo (biometrics) are required.
Find more information about visa requirement at: www.canada.ca/en/services/immigration-citizenship.html