Create your Canada Post account by signing up on their official page. You will be provided with a Canada Post Customer ID. Use it to access your account.
To define the Canada Post Shipping Calculations go to Configuration → Shipping → Shipping Providers.
Enable this method, as follows:
In the Canada Post row, click the Edit button.
In the Is active column, check the checkmark.
Click Update. The False option becomes True.
Click Configure beside the Canada Post option in the list. The Configuration window is displayed, as follows:
Enter the following information obtained from the Canada Post provider:
Canada Post Customer number
Tick Use Sandbox if you want to enable a testing environment.