Paint is a very basic drawing tool. It is not an image editing tool though some of its tools may be used to edit an image. For those that are skilled, it can be used to draw well but it is still a basic app. What that means is that it doesn’t have layers nor does it allow users to change/add an alpha channel. That said, it does support the PNG format which can save an image with transparency. Adding a transparent background in Paint is possible but it’s not simple. https://www.addictivetips.com/windows-tips/paint-transparent-background/