The Windows Scan app is particularly bad at this. When you scan a document, it saves the scan as a PNG in PicturesScans. This is a sensible place to save scans by default, but it doesn't tell you where. It just says it was saved. There's a button to view it, but this just opens the scan in the Windows Photos app, which (at least, last I checked) doesn't have an option to view the full path of the picture you're viewing or open the folder it's in!