XLSMMicrosoft Excel Macro-Enabled Spreadsheet
Files with XLSM extension is a type of Spreasheet files that support Macros. From application point of view, a Macro is set of instructions that are used for automating processes. A macro is used to record the steps that are performed repeatedly and facilitates performing the actions by running the macro again. Macros are programmed with Microsoft's Visual Basic for Applications (VBA) from within the Excel Workbook using the Visual Basic Editor and can be run/debug directly from there.
XLSXMicrosoft Excel Open XML Spreadsheet
XLSX is well-known format for Microsoft Excel documents that was introduced by Microsoft with the release of Microsoft Office 2007. Based on structure organized according to the Open Packaging Conventions as outlined in Part 2 of the OOXML standard ECMA-376, the new format is a zip package that contains a number of XML files. The underlying structure and files can be examined by simply unzipping the .xlsx file.