Visit as a tourist

Citizens from visa required countries, who wish to enter Canada temporarily, need to apply for visitor visas before they enter Canada.

Extend your stay in Canada

If you want to stay longer in Canada, you have to apply to extend your stay. You have to apply before the expiry date.

Visit as a parent or grandparent

With the parent/grandparent visa, you are allowed to stay for up to 2 years in Canada, without the need to apply to extend your stay.

The Super Visa provides multiple entries for up to 10 years, or for as long as your passport is valid.

Electronic travel authorization

Citizens from certain countries are exempt from applying for visitor visas. These citizens need an electronic travel authorization.

Exemptions are United States citizens and other designated countries.  Please check to see if you are a citizen of a designated country.

Transit through Canada

Visa-exempt foreign nationals need an Electronic Travel Authorization (eTA) to fly to or transit through Canada. Exceptions include U.S. citizens, and travellers with a valid Canadian visa. Canadian citizens, including dual citizens, and Canadian permanent residents cannot apply for an eTA.

http://www.cic.gc.ca/english/visit/index.asp