Customer map is a feature used in the admin area and once you setup this feature for customer each time when you need the customer company location you can navigate to this customer profile and click Map.
To use this feature first you need to have setup Google API Key in Setup ->Settings->Misc and in Google Developers Console make sure that you have enabled Google Maps JavaScript API for the project you have created.
This feature works with Google Map Latitude and Longitude. Get the Latitude and Longitude from google map and insert into the customer profile.