You are asking us to help you falsify a document! To be complicit in a conspiracy to deceive someone. To commit fraud? Electronic forgery?

Not cool.
Nothing personal, but it typically raises suspicions when a brand new member to a site that takes security seriously asks in his first post,
would people know...
I falsified...
how easy is that to find out?
I need a response ASAP
Perhaps you need to explain your intent to clear my confusion and to ensure there is no misunderstanding. We don't want to be getting into something unethical or nefarious.
I will say this, there is massive amounts of "hidden" editing, formatting, and change tracking information in Word documents that not only shows who (computer or Windows user) created the document, but when a change occurred and who did it. There are utilities to remove much of the hidden editing and change tracking data, but then the absence of that
normally present data is clear evidence of tampering. Therefore, I do not see how you could remove all traces of tampering - consequently, it would be very easy to find out if a Word document has been altered.
Yes, you can change the date of your computer and create a new fake document - but I have seen where doing that caused all sorts of problems with Windows itself, anti-malware programs and other applications when suddenly their critical files have future (and therefore invalid) timestamps.
That said, the new document would not contain any of expected hidden data of the original document - such as the original creator, or logical progression of edits and changes. Therefore, it again would be easy to determine it was not the original.
Best bet - take your lumps. Pick up any paper or watch any news show and note,
"The cover-up is always worse than the crime!" If I have misunderstood your intent, my apologies. But since we take security seriously, thwarting, not helping badguys is our passion. This site does not require identity authentication and you can remain anonymous (for the most part). Therefore, we cannot and will not assume all intentions or brand new posters, are good. I'd appreciate your understanding on that.