As a longtime Microsoft Office power user, I've found that demonstrating processes visually can make all the difference. Office 365 includes Ink Replay, a powerful feature in Word, Excel, PowerPoint, and the OneNote Windows 10 app (not OneNote 2016) that animates your ink strokes from handwriting, sketches, or drawings with a single click.
Ink Replay shines when recreating step-by-step processes, like solving a math equation, making it an invaluable teaching tool.
If the feature isn't visible on your ribbon, add it easily:

The Draw tab now appears on the ribbon with pens and the Ink Replay button.

You can't adjust playback speed, but use the forward/backward playheads to step through or drag the progress bar to any point.
Optimized for Windows 10 touch devices, it works on desktops too—though touch adds flair.
Note: OneNote 2016 lacks this; use the OneNote Windows 10 app (search "OneNote" in Start menu).
Ink Replay is an exceptional tool for annotations. For more, check The Simple Guide to Annotating: How to Annotate PDFs, eBooks, Images, and Websites—essential techniques for all digital docs.