PDF files are not meant to be edited. Adobe Acrobat offers limited editing capacities for them; the free Reader has none. More clearly: you cannot paste anything in a PDF file using just the free Reader.
OP, I believe, is asking if text cut from a Word document can be pasted in a PDF using ReaderX. This can be done to a limited degree by using the Sign tool- add signature - add text. Otherwise - need to go to the Standard version.
Europe, Middle East and Africa