Within a WordprocessingML document, annotations refer to various types of supplementary markup which may be stored inside or around a region of text within the document's contents.
example: : The types of supplementary information stored within a document may include: comments, revisions, spelling and/or grammatical errors, bookmark information and optional editing permissions.

Within a document's contents, annotations are stored in one of three different methods:

  • Inline

  • "Cross Structure"

  • Properties

These three forms are needed in order to maintain compatibility with both the legacy annotations functionality of current word processing applications and the requirements of an XML-based format (i.e. wellformedness of the resulting XML markup). These three forms are referenced within the individual annotation types described in the following sub clauses.