To activate billing, go to https://console.cloud.google.com/project/_/billing/enable
Learn more at https://developers.google.com/maps/gmp-get-started
Please visit https://developers.google.com/maps/documentation/javascript/get-api-key for further detail on authentication and Google Maps JavaScript API services.
Don’t forget to enable Geocoding API as well as Maps Javascript API to the project in Google Cloud Console and add Geocoding API to API key restrictions as well.