hope this information help you......................
If your application is approved
If your application is approved, you will receive the following:
A letter from the visa office confirming your approval. It will be sent by mail or by email, but not both. This letter is not your study permit. Take the letter with you to show to the immigration officials at the point of entry when you arrive in Canada in order to obtain your study permit.
If you are a citizen of a country that requires a temporary resident visa to enter Canada, the visa will be in your passport. For information on expiry dates, duration of stay, etc, please refer to After receiving a visa
If your application is refused
the visa office will send you a letter explaining why your application has been refused. An application might be refused for several reasons. For example:
You have not shown proof that you have enough money to support yourself while studying in Canada.
You have not satisfied the visa officer that your primary intention in Canada is to study.
You have not satisfied the visa officer that you will leave Canada at the end of your period of study.
source link -http://www.canadainternational.gc.ca/nigeria/visas/study-after-apres-etude.aspx?lang=eng