Google Maps require the usage of an API key, in order to work properly. This requirement was announced by Google, in June 2016.To Create Location in Google Map Plugin You need to create ‘Google Map API key’.
Create Google API Keys
Follow these steps to get an API key:
Step 1Go to the Google Developers Console .The first screen you will see in the Google API Console allows you to choose between creating a new project, or using an existing one. Click ‘Continue’ after you made a selection.
Step 2On next page, enter your project name and http referrer. If you leave the referrer field empty, then it’s possible for other users to use your key on their domains. More information see the guide Important Changes in Google Maps API V3 for Website Owners
Step 3Copy your genrated API key.
Step 4Then Go to WP Google Map > Setting page and paste your google maps API Key and save.
Now You can create location in Google Map.