ArcMap (also known as ArcGIS Desktop) is GIS software from ESRI
ArcMap is a full-fledged desktop GIS and is currently the the instructor standard for GIS. It reads and writes many geospatial data formats, provides a large set of processing and analytical tools, and can be used to create detailed maps.
ArcMap has been around for two decades, and is slowly being phased out by Esri in favor of ArcGIS Pro.
ArcGIS runs on Windows only, and requires an Esri license. If you would like to get a license to run it on your own computer: