Open XML File Format

Create a new blank document
Type "simple test"
Save this file as SimpleTest.docx
Close the file
Open Windows Explorer
Right mouse click on the file
Select Rename and change the file extension to .zip
Click OK to confirm
Right mouse click on the file
Select "Open with WinZip"
SS
Press Extract
C:\Temp\SimpleTest\
Press Extract
This will create a SimpleTest subfolder containing the following:
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Double click the word folder
Drag the document.xml file into NotePad
Locate the string "simple test" and replace this with a different string "advanced test"
Save this file and close NotePad
Now lets convert all these xml files back into a valid word document

Highlight all the subfolders and files in this folder
SS
right mouse click
SEnd To Compressed (zipped) folder
Rename the zip file to AdvancedTest.docx
Press Yes to confirm
Double click the file to open