Start with the title
NAFTA = North America Free Trade Agreement.
So the function this title describes is something to do with Free Trade.
It means that Canada, The United States, and Mexico have agreed to have certain commodities, manufactured products and services pass over the border(s) between the three countries without tariffs being imposed.
The idea is to let the market determine what the price of something is. Let competition determine what kind of money is made. The more successful the business the more tax revenue will be generated. Win Win for everyone.