A family of Microsoft word processing software products for creating web, email, and print documents.
If you pasted the material as text or an embedded object and not as a link to the original, there is nothing in the Word document that indicates its source, and nothing that shows whether the item was pasted or typed on your keyboard.
However, if the copying constitutes plagiarizing (whether by pasting or typing) or using copyrighted material without permission or acknowledgment, other people will easily be able to find the source on the web and compare it to your document. The lack of a direct link from the document to the source will not be any protection in that case.