Word automatically inserts a Private field when you convert a document from another file format. You don't normally need to insert this field yourself.
A Private field is formatted as hidden text and doesn't affect the document layout in Word. To hide a Private field, don't display hidden text.
Note
Because content that is formatted as hidden text can easily be made visible, do not use hidden text formatting to keep sensitive information private.
Syntax
When you view the Private field in your document, the syntax looks like this:
{ PRIVATE }
Note
This content applies to the desktop versions of Word for Windows and Mac (including Word with a Microsoft 365 subscription).
A field code tells the field what to display. Field results are what is shown in the document after having evaluated the field code. To toggle between viewing the field code and the field code results, press Alt+F9 on Windows or Option+F9 on Mac.