Adobe Acrobat DC is the best Word to PDF converter overall - but, maybe that's unsurprising, given the company behind the top ...

Salmela’s Automator action converts a DOCX file into a PDF from the right-click menu, making it a lot easier to convert the file, then open it up.

Click the "Files of Type" drop-down menu and select "Microsoft Office Word" to display only Word documents. Double-click the Word document to open and automatically convert the Word document.