What is MS Paint?
MS Paint, or Microsoft Paint, is a simple application for editing images that comes installed by default in Windows. MS Paint isn't a very powerful image editor, but it can perform basic image-editing tasks, such as cropping and resizing images, copying and pasting, drawing simple shapes, adding text to images, and saving images as JPG.
I always use MS Paint when I need to quickly crop a screenshot or an image I copied from the Internet, but I rarely save images with MS Paint. For example, if I want to post an image on Discord, I paste it on MS Paint, crop it, copy it from MS Paint, and paste it on Discord. The same workflow works with most social media websites.
For anything more complex than that, I wouldn't use MS Paint. Even placing two images side by side is difficult with MS Paint, and I'd rather use Inkscape for that.