It is easy to export a PowerPoint presentation or a Google Slides presentation to a video format, .mp4.
PowerPoint
Here a video, titled Using PowerPoint to Create an .MP4 Video (with music and auto-advance slides), is both an example and shows the steps for creating the video.
Here is a more sophisticated option in this video, title Using PowerPoint to Create an .MP4 Video with a Recorded Narration.
Google Slides
A Google Slides presentation can be exported to .mp4 using the add-on Creator Studio. You can include background music. Explanation here.