Note: Do not Print to PDF. This method of creating a PDF does not preserve the document's accessibility features.
Word 2007 and Word 2003 (Windows)
Exporting to an accessible PDF in Word 2007 and 2003 requires a plug-in such as Adobe PDFMaker, included with Adobe Acrobat Pro. With this plug-in installed, use the Adobe toolbar or the Adobe menu item to Save As PDF.
Word for Mac
As of Word 2011, it is not yet possible to export to accessible PDF from a Mac. Please look at some tips for creating an accessible PDF from a Mac from Portland Community College.