You use the Post Codes window to set up combinations of post codes and cities.
A post code can be associated with more than one city, and a city can be associated with more than one post code.
If you enter a post code in an address (for example on a customer or bank account card), and if there is more than one city set up for that post code, the program displays the Post Codes window with only the cities that are associated with the post code. You can then select the appropriate city. Conversely, if you fill in a City field before the related Post Code field, the program displays the Post Codes window with the post codes for that city.