Canada has a Temporary Resident Visa program that allows you to enter Canada legally for business or tourism purposes. A Canadian multiple entry visa allows visitors to come and leave Canada without having to re-apply.
A visitor visa is an official document attached to a passport that allows individuals to travel to Canada.Tourist must fulfill some requirements for getting visa as he /she must be healthy, must have a valid passport, proof of who you are or other travel documents, financial report etc.
If you are visiting Canada for meeting relatives or any other purpose you may need a letter of invitation or intend. You are not being permitted to enter Canada if you have a criminal conviction