Please read what CIC require:
There is nothing wrong if you attach some kind of recommendations or reference letters about your character and intention of visit to Canada.
All required documents must be included with your application:
You must have a valid travel document (such as a passport).
Two recent passport photos of each family member are required. Make sure these photos meet the requirements.
Enclose the application fee. Your fee will not be refunded, even if your application is not accepted.
You must provide proof that you have enough money for your visit to Canada. The amount of money may vary, depending on the circumstances for your visit, how long you will stay and whether you will stay in a hotel, or with friends or relatives. You can get more information from the Canadian visa office in your country or region.
You may need to include other documents. These documents could be identification cards, proof of employment, a letter of invitation from relatives or friends in Canada, or a proposed itinerary. Check the website of the visa office responsible for the country or region where you live for more information.
details:
http://www.cic.gc.ca/english/visit/apply-how.asp#step3