This article explains how to insert a Word document into another document, even if the copied document contains headers and footers. Instructions apply to Word 2019, Word 2016, Word 2013, Word 2010, and Word for Microsoft 365.
How to Insert a File into a Word Document – Link or Embed Attached Files in Word
If you have an existing Microsoft Word document that would complement a document you're working on, you have a few options. If you want to add an entire document to a second Word document, your best option is to know how to insert a document into Word.
Word merges the document into the current document without changing the formatting applied to both documents. Graphics, tables, shapes, and other objects in the existing document are also transferred to the new Word file.
Start Word and open the document into which you want to insert another Word document.