A file with the .pptx file extension is a Microsoft PowerPoint Open XML (PPTX) file created by Microsoft PowerPoint. You can also open this type of file with other presentation apps, like OpenOffice Impress, Google Slides, or Apple Keynote. They are stored as a compressed ZIP file, which use a bunch of other files with formatted text, images, videos, and more to open them.
PPTX files are used in Microsoft PowerPoint, a presentation program used to display content in a slideshow format. Each slide can contain graphics, formatted text, videos, music, animations, and more.