The chances are that it uses Content Controls linked either to document properties such as author, or to "Custom XML data". If you go to Insert->Quick Parts->Document Property.. And insert one of the items listed there in more than one place(Windows Word 2007 or later) you should see this behaviour. You can create your own content controls and Custom XML Data parts to do the same thing, but you need to use code (e.g. VBA) or in Word 2013, to use a feature in the Developer tab.
There are other ways it can be done. There are descriptions of most of them at Greg Maxey's site here
If your organisation uses Sharepoint, all that is required to create a similar kind of control is to create a new data column in a document library. Sharepoint then typically creates the content control and XML part dynamically when the document is opened. This is not covered on Greg's site.