When you open a master document in Microsoft Word it might give you a scare. Instead of showing the document text all you see is some links. All the subdocuments will appear as hyperlinks in the master document.
To see the entire master document with sub-documents go to View | Outline. The Outlining bar will appear and it hasn’t changed much (or at all) for many years. Here’s two versions of Word with the Outlining ribbon.
Click Outlining | Expand Subdocuments button so the content of the subdocuments will be visible. Again when the Collapse Subdocument button (“Expand Subdocument” transforms to “Collapse Subdocument” button) is clicked the links appear.
Collapsing a sub-document and showing links instead of the full text can make the master document easier to manage and improve Word’s performance on older machines.
To see the document as it will appear printed or saved to PDF, also choose ‘Show Document’
By clicking the hyperlinks of the subdocuments each subdocument will open in a new document window independent of the master document. Or double click the small subdocument icon (above the lock icon).
The small lock icon indicates the subdocument is locked and cannot be edited by others. By default subdocuments are locked in the collapse mode
To delete the subdocument click the small the subdocument icon and press the [delete] button. Although the subdocument link will be deleted from within the master document the sub-document file will still exist in its saved location
TIP: It is always recommended to move or delete the subdocuments from within the Master document only. Otherwise the subdocuments will go missing from within the master document. Also while printing the Master document you can choose to expand or collapse the contents of the subdocument.