If your items are small and can be sent by Letter Rates, use dotCOM because those rates are based on dimensions and weight, with a maximum of 2cm and 500grams.
On dotCOM you can ONLY use Flat Rate Shipping from an International location.
If your items are bulky, use dotCA, and Calculated Shipping, which not only allows you to choose more services, but also bases the buyer's costs on weight, dimensions, and destination.
https://www.canadapost-postescanada.ca/cpc/en/tools/find-a-rate.page
And then there is Free Shipping, which is a version of Flat Rate.
Don't panic.
Free Shipping just means you are putting your shipping costs into your asking price.
Don't use Free Shipping for overseas destinations. It will bite you.
You may already know this @gypseyrobert , but your question will be viewed by many others.
