Policy & plotting locations

As a new user here ,

  1. Is this a free platform that allows to use the map in both private and commercial websites ?
  2. Is there away to plot google map locations that i have in a seperate excel file ? How?
  3. Is there a way to turn on and off polygons that i draw? And can yoo show seperate 2-layers seperatly and one on top of the other on the same map?
  4. What is the best way to use the map to reach quickest download time for the user ?
    Thank a lot

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