Blocking out the right hand bottom area so nothing can be entered there are a stamp goes there

[EdGood]

Hi all
We print out our Word documents on paper with a rectangular ink stamp in the bottom right hand corner of each page (and a signature).
We have a standard footer in Word that currently spans the entire width of the Word documents we print out. The stamp actually goes above this (it could be compacted and shifted to the left if needed).

How do we "block out" this area, or put a guide or grid there (or any other option) so we know not to put text there that will cover the stamp when printed.

Thank you for solutions!