From step 4 of the Mail Merge Wizard, you can add addresses, greetings, and other personalized merge fields.
Address block with name, address, and other information
For Help on an option, click the question mark , and then click the option.
Greeting line
Other fields of information
Note If you insert a field from the Database Fields list, and then later switch to a data source that doesn't have a column with the same name, Word won't be able to insert that field information into the merged document.
Electronic postage
In order to add electronic postage, you must first install an electronic postage program, such as one you purchased from a service on the World Wide Web.
If you do not have an electronic postage program installed, Microsoft Word prompts you to install one and offers to connect to the Microsoft Office Web site. There you can get more information and links to other sites that offer electronic postage.
Postal bar code
You must select a label or envelope type that supports the POSTNET bar code.
Note The Postal bar code option only appears if you are using the U.S. language version of Microsoft Word.
Notes
You can't type merge field characters («« »») or insert them by using the Symbol command on the Insert menu.
If the merge fields appear inside braces, such as { MERGEFIELD City }, then Microsoft Word is displaying field codes instead of field results. This doesn't affect the merge, but if you want to display the results instead, right-click the field code, and then click Toggle Field Codes on the shortcut menu.