When files are deleted from their folders, they get stored temporarily in the deleted-items folder before they are permanently deleted. The deleted-items folder in Windows is called the Recycle Bin, while the one in Mac OS X is known as the Trash. Files that are deleted can be retrieved from these folders if they have not been emptied yet. Once they are permanently deleted, the files will not be visible anymore in File Explorer/Finder, although the data might still be intact in the storage device until other data overwrite it. Cloud-based services also have deleted-items folders, which you should look into if you had the files synced in cloud storage.