Although iPhoto has been replaced by Photos, the core of this issue still applies. I'm replying to this thread since it's the first Google result when people are looking for information about 1) living in US and sending a print product to a friend in Canada or 2) living in Canada and sending a print product to a friend in the US.
Unfortunately the bottom line is it's impossible or very complicated. For some reason Canada and a few other countries (Australia, New Zealand, Japan, Hong Kong, Singapore, and the United States) seem to be really special where the ordering options are more limited based on the billing address of the credit card. There's a good Apple help article that explains this - but it's hard to find. Here is the link:
Photos for Mac: Ordering overview
The work-arounds I've thought of for this ordering issue are:
- Use a screen sharing program to have your friend complete the purchase using their iTunes account (and Credit card) within your Photos app.
- Re-ship the print product after purchasing and shipping into your home country.
Many help articles will mention you can go to Photos > Preferences, change the store, and are able to ship to that country. The key is when changing between countries, the available credit card billing addresses are reduced.