You have to add your Google Map API under Setting.

How can I create a google map API?
Click Here to get an idea of how to create a Google Maps API.

Please enable two APIS of google.
1) Maps JavaScript API, Maps Static API( For Admin preview under the Settings page ) – for display maps in frontend
2) Geocoding API – searching in maps in frontend – need billing for using this API

Steps to create an API:
– First you need to go to the https://console.cloud.google.com
– Create new project
– Select that project and Go to the APIs & Services
– Enable the Google Maps JavaScript API, Maps Static API & Geocoding API
– Go to the Keys & Credentials
– Edit/Create new API Key and Set an application restriction by Websites and set your domain as per the video instruction like *.YourDomain.com, *.YourDomain.com/*, YourDomain.com and YourDomain.com/* and add that key under the Front Map API and Admin Preview
– Create new API key and Set an application restriction by IP addresses and set the IP 159.89.127.203 and add it under the Geocoding API