Spreadsheets to Maps

The best format for mapping point locations is a spreadsheet, which can be saved as a CSV file (Comma Separated Values). The CSV file format is a universal spreadsheet format type that you can export from Excel or Google Sheets. It has the advantage that when you open it as a spreadsheet you can edit and add to it using all of the tools available in Excel or Google Sheets (things like autofill and sort to help with quality control), and then once you are through editing it you can import it into Google My Maps, Google Earth Pro, and EnviroAtlas. 

Various of the mapping platforms also use file formats such as SHP (used for ESRI ArcGIS, Google Earth Pro, EnviroAtlas, EJScreen) and KML/KMZ (used for Google My Maps, Google Earth Pro, EnviroAtlas). While CSV spreadsheet files can be used for point data, SHP and KML/KMZ file formats can be used for polygons and lines (shapes) as well as points. In addition, KMZ files can be used for adding image layers to Google Earth Pro. The disadvantage is that you can't open SHP, KML or KMZ files in spreadsheet programs, so you can't edit them without coding. 

Of course any file that you plan to use for mapping will have to contain geographic data, such as street addresses or Latitude and Longitude.