There are two methods using which you can easily change or restore default icons for a Folder in Windows - Using Properties or desktop.ini file.

You can change nearly any desktop icon on both Mac and PC using the “Get Info” menu or the “Properties” menu.

Apple makes it easy to change icons for files and folders on Mac. Here's how it works, along with tips on using images or changing the folder icon color.

It's easy to change the icon size on a Windows 10 PC for files, folders, or applications using the View menu in your files program.