I have read the answer of this question in this link https://community.esri.com/t5/arcgis-javascript-maps-sdk-questions/draw-polygon-save-it-as-a-shapefi.... But now I want to understand more about how to assign the shp file to .prj file. It has been explain that assign it using the Web Mercator Auxiliary Sphere projection. Can someone explain or share it here how it works? I really need to create polygon to shp file and import this file in arcgis online. THank you