To animate a line graph in PowerPoint, you need to open the slide, draw the Graph add the labels and then animate the graph as explained here.

Learn how to add & use the Draw tab in PowerPoint. It consists of drawing tools to draw on your slide. Make sketches with pen, pencil, and highlighters, etc.

Google Slides are an easy way to create and share slideshow presentations. You can even draw free-form on Slides when you're creating them. Here's how it works.

You can easily draw in PowerPoint to mark and edit slideshows, or create your own designs, especially if you're using a touchscreen.