Preparation

When you have completed your presentation in PowerPoint, you can record it with sound (if you have a microphone) and ideally a small video of yourself (if you have a webcam). The movement of a pointer can also be recorded.
Please, put a short title of your presentation and/or your name in the footnote of all your slides for information of audience entering the room in the middle of your presentation.
The video appears in a small window at the bottom of the screen. Design your presentation so that this corner is not used by titles, text or pictures.
It is also possible to change the format in PowerPoint to get the slides on about half the screen and the video on the other half.
Note:
• Use a neutral background such as a white wall.
• Test your microphone and verify that the sound and video are correct on
some slides before final recording

• Sound and video are linked to each slide and can be erased after selecting the video in the corner and re-recorded in PowerPoint on a slide-by-slide basis if necessary.
• Do not speak when changing slides.
• Check your recorded file before uploading it.

Recording

When you are ready for the final recording, put the presentation in full-screen mode or Slide Show mode.
Select Slide Show > Record Slide Show

The image from your camera should appear in the lower right corner.
You may have to choose the correct camera and microphone under their icons.
Modify the pointer to laser if needed.
Choose from two options:

• Record from Beginning – to record from beginning of a presentation
• Record from Current Slide – to record from a specific slide

When you are ready, select Record and start speaking.
Present yourself then your slides.
At the end of the presentation, stop the recording and save the PowerPoint file.

• Select File > Save.
• Choose pptx format

You can then export the PowerPoint file to an mp4 video file.

• Select File > Export
• Choose file format MP4

The PowerPoint or mp4 file is generally more than 100 Mbytes.
More info: https://support.microsoft.com/en-us/office/record-a-presentation