PPTM, PowerPoint Open XML Macro-Enabled Presentation (.pptm)
The PPTM Presentation file format
PPTM files are one kind of presentation files that can be used and created by Microsoft PowerPoint. Microsoft PowerPoint is a program that creates slide shows and presentations comprised of a collection of slides. Those files include the layout of the presentation, images, text, and embedded macros. This ability of containing embedded macros is what sets PPTM files apart from PPTX. While PPTX files can include macros, only files with the PPTM extension can successfully execute them.
Technical details of PPTM files
PPTM file are based on the Open XML Document format which was introduced with Microsoft Office 2007. Files with the PPTM extension can only be opened in PowerPoint 2007 or later, or with earlier versions that have an Open XML component installed.