Esri is a company specialized in Geographic Information System tools. ArcGIS, ArcMap are two of the most commonly used and powerful tools among all the GIS tools provided. As more and more data in incorporating geo-coded information to provide details of certain events, GIS has become more and more popular among data analysts and business intelligent.
ArcGIS and ArcMap are available for download on arcgis.com. The price for these tools are very expensive. If you belong to an educational institution, you may want to check with the related departments to see if such tools are provided free of charge within your institution. For businesses, contacting Esri getting a contract might be a better idea based on the scale of business. Here I am using ArcMap under free trial. You can sign up to use the software free of charge for a certain period of time.