This is where you insert the references or referenced fields into the current document. References are referenced fields within the same document or within sub-documents of a master document.
The advantage of entering a cross-reference as a field is that you do not have to adjust the references manually every time that you change the document. Just update the fields with F9 and the references in the document are updated too.
Depending on the field type that you select, you can assign conditions to certain functions. For example, you can define a field that executes a macro when you click the field in the document, or a condition that, when met, hides a field. You can also define placeholder fields that insert graphics, tables, frames and other objects into your document when needed.