Wolfram user manual: Addresses

Addresses

One mailing label is created for each address in a location. Some points to note:

The mailing address is taken as the home address in the user's contact record, and is not necessarily the same as the property address.
If there are multiple owners listed for an address, we generate only one mailing label. The label is addressed to each owner but we pick a mailing address of only one of the owners.
In some cases one user can own multiple addresses in a single property. In this case, the user will get one mailing label for each property owned.

These instructions were snagged from the Postal Rate Commission's web site.

Go to the web page that lists all properties.
Select a property.
On the property page, select the link to "Download owner list for mailing labels".
This generates a text file in comma separated variable format. Save it somewhere on your hard drive (the default name is "labels.tcl")
Open a new document in Microsoft Word.
Select "Mail Merge" from the Tools menu. The Mail Merge Helper will appear showing the three mail merge steps.
Under the first step, "Main document," click the button marked "Create" and choose the "Mailing Labels" option.
Under the first step, "Main document," click the button marked "Create" and choose the "Mailing Labels" option.
Under the second step, "Data source," click the button marked "Get Data" and choose the "Open Data Source" option. The "Open Data Source" box will appear.
At the bottom left of the "Open Data Source" box, use the pulldown arrow to change "Files of type:" from "Word Documents (*.doc)" to "All Files (*.*)."
Find labels.tcl. Select the file and click on the "Open" button.
When the box appears asking you to set up the main document, click the "Set Up Main Document" button.
In the "Label Options" box, select the Avery number of your labels and click "OK."
In the "Create Labels" box, click the button marked "Insert Merge Field" and select the appropriate fields to create the label master. Use spaces and returns where necessary.
When all the fields are in address format, click "OK." The Mail Merge Helper will appear again.