To create a Composite field, you do not need to mark-out an area of a page: simply select "New" from the Fields menu and enter its definition directly into the Field dialog. There is a drop-down list of the fields already in the document and pre-defined symbols to speed the setting-up process.
Pre-defined symbols are used to contain commonly-used data values related to documents such as the file and page details, dates and PJL commands. They can be recognized by their leading underscore character.
You may specify a constant value for a Composite field or you may set up a condition. For example, they can check for the presence or absence of a string, whether a field value has changed, set up counters and prompt the User to input data.