It’s really not… There are several pretty straightforward ways to do it and they’re all pretty old standards. Save as > select PDF as the file type. Or if you have Adobe Reader/Acrobat installed, word has a button right under save as that says Save As Adobe PDF. Or you can print to PDF using the Adobe print function in the printers. Lastly windows has a built in PDF printer by default. All of these work pretty damn reliably. If you can’t save a PDF from a word doc, it’s either your computer or you.