Word's sample templates often use the specially set up Document Property Content Controls. You can do the same thing. These are built-in Mapped Content Controls that you can repurpose.
Repeating Data Using Document Property Content Controls and Other Mapped Content Controls




Greg Maxey has a number of pages on using Content Controls, especially Mapped Content Controls. He discusses the built-in ones in his pages Enhanced Document Properties AddIn and Repeating Data (Populating Multiple Like Fields) by Greg Maxey.

Addressing your question in the title: Content Controls are not fields, although they can be used inside fields. Paul Edstein has posted several excellent tutorials on fields that are pinned to the top of this forum as well as the Mail Merge Forum. Graham Mayor has a number of articles about fields on his site. I especially like his Add-In http://www.gmayor.com/export_field.htm.