That all depends on what you're trying to do.

You could, for example use Word's mailmerge tools to generate different versions of the document according to what you input into different fields in an Access database, Excel workbook or even a table in another document. Or you could use a document with formfields and field coding to generate the text variations, based on selections from one or more dropdowns. Yet another option would be to use content controls and macro coding.

More information would be needed before specific advice applicable to your situation could be given. For example, are the property data already stored in a database/spreadsheet/Word table that a mailmerge or other process could use? Are you trying to generate multiple versions of the one letter or of multiple kinds of letters and other documents?

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]