Visitor Visa and Visitor Record
A Visitor visa also called a Temporary Resident Visa. It allows you to enter Canada as a visitor. Once you enter Canada on a visitor visa, even if your passport is not stamped by a border services officer you can stay for 6 months. If your passport is stamped by a border services officer, you need to leave Canada by the date as indicated on the stamp.
If you are in Canada on a visitor visa and want to extend your stay, you can make an application for a Visitor Record from within Canada. A Visitor Record is not a visa.