I can use instruction in Geotagging. I'm a beginner

I have WIX Editor and I’m a service-based business. I provide a service to the entire county in my state. I also have some landing pages for specific cities. I took a course that said to go to the geo tag generator and insert the code in the page. What would I do about the entire county I service? And for landing pages, should I create one for each page since each one is for a different city?