Note: This manual is for osCommerce v4.
Create a new account in Google (if there is none) or login to the existing one.
Nothing can be done until billing is switched on (trial gives $300 for a new account for a year).
Go to the console page for developers.
By default there is nothing in management panel section for the new account or if API has not been used yet.
Click on Enable API button.
If the project in console has not been created yet Google system will ask to create it. Click on Create project button.
Indicate the project name, read Terms of Service, agree with them and click on Create button.
Fill in the data and click on Go to Credentials button.
Then click on What credentials do I need? button.
Fill in the fields:
Accept requests from these HTTP referrers (web sites): domain name of the website (it is an optional field, when you would like to use this service for this site only).
Note: indicate only domain.
Click on Create API key button.
You will see the generated API key. Click on Done button.
The key is filled in in the section Settings/ Google settings under Map Key API tab.
Then you will see the following screen.
In order to pass domain verification on Credentials tab click on Domain verification link.
Click on Add domain button.
Indicate dns-name of the website only (for example mysite.com)
Important: Your site must be registered on Search Console with an https:// URL or with the domain name provider verification method.
On the page https://www.google.com/webmasters/verification/verification you can pass one of the suitable procedures of verification of a website owner. After that you will see the list of allowed domains.