Adding voice-over to Google Slides/Presentations

Google Slides does not have built-in functionality to insert audio, so how can you record narration and have it play over a slide? Here’s a technique I use. Note that you need to do this for each slide that has audio


Install the Screencastify extension (if you don’t already have it).


In Screencastify, choose “Record Tab.” You’ll get a countdown (3-2-1), then just start speaking. When done, choose Stop from the Screencastify icon.


You have now created a video of your screen with the audio you want.


In Google Slides, go to the appropriate slide and choose Insert...Video. Click the Google Drive option. You’ll see the “video” you just created. Insert it.


Click on the icon for the video. Resize it so it’s much smaller. Click Video Options. Select “Autoplay when presenting.” The video will now start as soon as the slide opens, providing your narration. You can also trim off time from the beginning or end, if needed.


If desired, you can hide the video icon by creating a shape with the same color as the slide background and dragging it over the icon.
Here’s all this in action.  Open the presentation and click Present.  Make sure your sound is turned up.

You can use a similar technique for PowerPoint 365 (the online version of PowerPoint). Note, however, that you'll need to put the video on YouTube for it to work.