With FileStar you can easily convert PPTX to PDF. Accessible directly in your right click menu for single or batch PPTX processing.How to convert PPTX to PDF:
1. Download and install the latest version of FileStar. (https://filestar.com)
2. Right click on one or more PPTX file(s) on your desktop and select Convert with FileStar.
Type convert "pdf" in the search box.
3. Press Run.