I wanted to change the file extensions of multiple files (10+). Instead of having to select each of them and renaming them to add a .pdf, for example, at the end, I would like to do it in one swift motion. I googled it and it seems like alot of these options are outdated (downloaded a program but it didn't work). Plus, it kind of looked a bit shady, installing other programs. I figured it would be wiser to just ask here and get the safer, more reliable option. Does anyone know of a program that can do this on Windows 10?