The GeoGrid Widget uses Google's Places API to autocomplete business names and addresses when a visitor searches. To enable that, you supply your own Places API key. Here is how to create one.
Create the key in Google Cloud
Go to the Google Cloud Console and sign in.
Create a new project, or select an existing one.
Open APIs & Services > Library, search for Places API, and enable it. Enable Maps JavaScript API as well if prompted.
Open APIs & Services > Credentials, click Create credentials, and choose API key.
Copy the key that is generated.
Restrict the key (recommended)
In the key's settings, restrict it to the Places API (and Maps JavaScript API) and to your website's domains. Restricting the key stops other sites from using it and running up your Google bill.
Add it to LocalOptics
Paste the key into the GeoGrid Widget's autocomplete API key field. See The GeoGrid Widget for where that lives.
Google billing: the Places API is a paid Google product with a monthly free tier. Usage is billed by Google, not by LocalOptics.