Saving PowerPoint as a video: 

• Click on the File tab to show file options.
• Scroll down and select Export and navigate to Create a Video.
• Select your video settings preference (video quality, timings and narration, video size).
• Click on Create a Video.
• Choose a filename, saving location and video type (.mp4 or .wmv).
• This step may take some time. The progress bar at the bottom will let you know.