When printing either the Word or the PDF files, it is essential that you set the paper size correct in the application and in any printer dialogue boxes on your PC/Mac. If you are printing on A4 paper, then you need to set the paper size to A4 not Letter or any other size.
If you don't set the paper size correctly then the files will be resized according to the paper size you have selected, despite having A4 paper loaded in the printer.
Printing PDF Files
When you print your PDF file, it prints out smaller on paper than the Word or other file it was created from.
When you print from Adobe Acrobat Reader, you will see this dialogue:
You will see that 'Print Scaling' setting is by default set to 'Shrink to Printable Area? That's the one that's shrinking your PDF when you print it.
Change the setting to 'None':
Now, when you print the PDF it will print at the right size.