The Document Property is a Quick Parts feature in Microsoft Word to add Building Blocks which are text used often saved in a Gallery.

In Microsoft Word, you can insert built-in or custom fields into your Word document that may change within your document. Learn how to insert a Text field in Word.

How to Increment a Counter in Word. Microsoft Word includes fields that enable customized data insertion, including Word Count, Page Count and Sequence, which is used to create incremental counters.

Microsoft Word fields house instructions that help you create dynamic content; they're flexible and powerful, if you know how to use them.