Office allows users to include VBScript to add dynamic functionality in documents. Word/Excel/Powerpoint also support ActiveX “Controls” and “Fields” These functions can be used to either launch macros or embed OLE embedding. DDE (dynamic data exchange) is a semi-legacy Windows feature used for displaying data from external data sources in the current document. A lot of what is mentioned below is specific to Word, Excel or Powerpoint however don’t forget that Office actually includes Word,. Excel, Powerpoint, Access, Outlook and OneNote.”]
Source: http://pwndizzle.blogspot.com/2017/03/office-document-macros-ole-actions-dde.html