Does this mean that you already have a CE Mark for Europa?
If you have met the regualtory requirments for the countries you are exporting to (for the U.S. you will need a 510(k)).
The documents are fairly easy. You will need a "Commerical Invoice for Customs"
It is what you would expect on any invoice. However, a statment may be needed to either avoid or pay reduced tarrifs.
For AU, we do something like:
"Certificate of Origin on File"
(Medical Equipment Enclosed)
Product Manufactured in the USA"
"Note: with reference to "The USA/Australia Free Trade Agreement", this is to confirm that the goods shipped to ABC Ltd are a 100% manufacture of USA and are eligible for preferential Duty Rate."
I do not if this will help, but I would suggest contacting the government. The following is some Email addresses that should get you started.
Good Hunting.
International Trade Canada (ITCan)
https://www.itcan-cican.gc.ca
Canadian Trade Commissioner Service
https://www.infoexport.gc.ca/
Investment Partnerships Canada
https://www.investincanada.gc.ca
Team Canada
https://www.tcm-mec.gc.ca/
Trade Negotiations and Agreements
(broken link removed)