Geoip. Targeting my visitors location.

I know its possible to find out where my sitevisitors are from, using geoip. for instance: https://www.maxmind.com/app/ip-location
Then display special adds for their country.

But I don`t know how to do it? Is that possible to use on my wordpress site?

Anyone have any experience with it? Is it difficult coding?

In general all tips about tips topic will be highly apriciated ??