Dear @PREININGER, DAVID,
Thank you for posting your question in the Microsoft Q&A forum.
Based on your description, you wonder how to copy docx from Word desktop app and paste to Work web version.
Here are some suggestions you can try:
Open the document in Word for the web
Go to https://www.office.com.
Open Word for the web.
Open the target document.
Make sure the document is in Edit mode:
Click Edit Document > Edit in Browser.
Or you can copy data from Docx and paste into Web version
Copy the content from Word desktop using Ctrl+C, open the document in Word for the web in Edit mode, then paste using Ctrl+V (or Ctrl+Shift+V to paste text only if formatting issues occur).
For more detail information, you can refer to this article Copy and paste in Office for the web
I hope information above meet your expectation, if it does not, please leave the comment below so I can support you more effectively.
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