ArcGIS account requirements
Anyone can use Explorer to view sample maps as well as search for public maps on ArcGIS Online.
To use your maps (both those you've created and those shared with you) in Explorer, you must have an ArcGIS account. ArcGIS Online and ArcGIS Enterprise are supported. Portal for ArcGIS 10.4.1 is also supported.
To create maps for Explorer, you must have an ArcGIS account. If a member of an organization on ArcGIS Online or ArcGIS Enterprise, you must be a level 2 member. Portal for ArcGIS 10.4.1 and public accounts on ArcGIS Online are also supported.
Data requirements
Your maps can include data from ArcGIS Online and ArcGIS Enterprise. For details, see Make maps.