There are other methods to recording your presentation with webcam video that are listed on this page.
These alternative programs may allow for greater flexibility in how you want your presentation recorded but they also assume a higher level of familiarity and comfort with working with tech/software.
Much like when using Zoom to self-record - we strongly suggest everyone always do some test records and review the footage to make sure the video size, quality, video and audio are coming through as anticipated before proceeding to record your entire presentation.
In this tutorial, our guide indicates this ability to record your slideshow with webcam video will not be in PowerPoint 2013 but *should* be in included with PowerPoint 2016, 2019 and Office 365
For advanced users who want a little more control, such as how big your webcam video size is or what it is located as an overlay, you can record your presentation in OBS.
Cost: Free
OS: Windows or Mac
Download @ https://obsproject.com/download