There are dozens of programs that can be installed on your computer to open Microsoft Office documents and other office or rich-text documents ( for example PPTX Open File Tool)
Also you can try OpenOffice. It is available for all major platforms including Microsoft Windows, Apple macOS, and Linux.
Google Docs, available from Google.
since you are not the op, you really need to give more details. what is the file extension and what is the model of the device? are you getting any error messages if so what are they?