Hi sqzdog,
What you would do is install the macro in to, say, a new document, then run the 'UpdateDocuments' sub. This will display a prompt for you to navigate to the folder where the documents are and then it will automatically insert some text into the footer of every document in that folder.
As coded, the macro I posted will put the words "My Footer Text" into the main footer of every document in a chosen folder, in 15pt Arial bold. You can change any of these attributes, or use different ones (eg italic, red text, etc).
If you don't know how to install/use a macro see:
http://www.gmayor.com/installing_macro.htm