All you need is a virtual printer which can create PDF files. It's also called a virtual PDF printer. This virtual printer is used in the same way as any other printer in Windows, with the difference that the PDF printer creates PDF documents.
A free easy to use PDF printer can be downloaded from this page. Just click the download link to the right of this article to download the latest PDF24 Creator which installs you a virtual PDF printer to print to PDF.
To print a Word document to PDF do the following: This PDF printer has a Word to PDF function. Open the PDF24 Creator and drag & drop your Word document into the right area of the window. The Word document will be converted to PDF if you have Microsoft Word or another Word document reader installed.