Free Editor is advised only if you really need a free editor, or an editor for multiple different formats. In our everyday lives, we use a number of different programs to edit the various file types ...
XLS files are Excel workbook files created in Excel 97 or Excel 2003. The 2007, 2010 and 2013 versions of the program use the XLSX format by default to save workbooks, but can also use the XLS format.