1. Follow this link and click on Get a key:
2. Agree with the service Terms of Service:
3. Choose a name for your new key and specify the websites on which the key usage will be allowed. If you don’t need any website restriction, just put an * in that field (but don’t leave it blank, unless you are having issues with *! See comments for further information). Then click on Create:
4. Write down your brand new API key, and click OK
5. Locate the file that contains the Google Maps script code on your website, and append your API key to it as a parameter:
If there aren’t other parameters, just add ?key=YOUR_API_KEY at the very end of the src path; otherwise, add &key=YOUR_API_KEY instead, like this:
Obviously, in both cases you must replace YOUR_API_KEY with your actual API key code.
6. Your API key should be up and running within 5 minutes. Enjoy!