The eTA is electronically linked to this passport. You do not have anything to print.
However, to board your flight to Canada, you must have two essential documents:
When you check in for your flight, the airline will confirm that you have an eTA and proof of status in the United States. When you arrive in Canada, a border services officer will check all your documents.
NOTE: it is necessary to redo a new eTA application if you obtain a new passport.