PDI is a file extension specific to Microsoft PowerPoint. It is an application that is a component of many versions of Microsoft Office and Office365 packages for both Windows and Mac systems. It is a tool that allows you to create multimedia presentations in the form of a collection of slides.

PDIs are files used to store data that is exported or imported by the program. However, this applies to the content that is powered by Power Point. The PDI format was used in older versions of the program. Today it is rarely used and is considered obsolete.