Can I use Pay per use in Cuba with a Prepaid account and if so how does it work.? Thank you.

No, you cannot roam in Cuba with a prepaid account. The only country you can roam with Koodo Prepaid is in the U.S. https://www.koodomobile.com/en/help/long-distance-travel-and-roaming-prepaid

Ok thank you and probably time to switch

Most, if not all, prepaid services do not offer roaming to other countries. You will need to sign up for a postpaid account to access the Easy Roam feature or similar ones offered by competitors such as Bell and Rogers.