Google Maps API

Hi guys, how are you, thank you for this opportunity to ask question and maybe get answer.
My website developer used ultimate-fields plugin a lot of time ago, about a year or 2, and now i am getting on the website (i have a field that should show a map):
GEO Code was not successful due to this code: OVER_QUERY_LIMIT

I registered to google maps and ready to pay for the location service if needed, but where should i insert the API ? thanks a lot for your help!