Alternative programs include Kingsoft Presentation (multiplatform), Apache OpenOffice Impress (multiplatform), Ability Office (Windows), and Apple Keynote (Mac). Several other presentation programs can open PPSX files but they may not fully support the formatting of the slide show files. The application is also available for Android and iOS devices. PowerPoint is the best option for opening PPSX files because the software fully supports the formatting of the slide show, which includes the placement of text and images. You can open, edit, save, and convert PPSX files with Microsoft PowerPoint in Windows and macOS.