Canadian permanent residents do not need visas to go to Cuba for holidays if they have purchased a packaged tour, in other words, you have purchased from the agency flight and all-inclusive hotel stay in Cuba. If this is the case then a visa will be given at the Cuban airport of entry.

At the same time, if the purpose of your trip is business or you travel as an individual and stay at a private place like an apartment, house, etc., then you must obtain a visa beforehand. Apply for Cuban visa here: http://cuba.visacenter.ca