We used a little trick to make this Realistic Handwriting Text Animation in PowerPoint using the Design and Screen Recording Tools. The Ink Replay option is only available in PowerPoint 365 and PowerPoint 2021, which is required to accomplish the animation. So, you might not be able to make the Handwriting Effect in earlier versions of PowerPoint.
The trick was to draw all the characters using any Pen from the Draw tab. Then record the Screen using the Screen Recording option from the Insert tab and then hit on the Ink Replay command from the Draw tab.
That way, PowerPoint will record all the strokes you use to draw the characters and will then convert the recording into a video. You can then set the video to Play Automatically during the slideshow and that will create a Realistic Handwriting Animation. For more information, you can watch the tutorial video.