Files with IFC extension refer to Industry Foundation Classes (IFC) file format that establishes international standards to import and export building objects and their properties. This file format provides interoperability between different software applications. Specifications for this file format are developed and maintained by buildingSMART International as its Data Standard.
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.
You can also convert IFC into many other file formats. Please see the complete list below.