Inkscape is vector-drawing software. Vector graphics are different than the more common raster graphics. A raster graphic like a JPG says, “The top left pixel is blue. The next pixel to the right is red. The next pixel…” A vector graphic says, “There’s a blue line from the top left to the right of the image. There’s a red circle whose diameter is half the length of the line.”
Vector graphics are superior to raster graphics for things like illustrations. You know how when you zoom into a photograph it eventually gets blurry? That’s because you’re just making the pixels bigger. A vector graphic is just a description of how to build an image, so you can zoom forever without getting blurry; the image will just re-draw at the new size.
Inkscape is really the only game in town for free vector drawing. I’ve used it for things like the logo of our podcast, Ten to One. That’s why I donated my October creators donation to Inkscape.