Adding Geo-location or Geotagging as WordPress calls it, to your posts in WordPress.com is quite simple and is baked in to the platform. It is disabled by default so the first thing you need to do is enable the service.
To do this, on your WordPress dashboard Users > Personal settings to bring up this screen.
and click to enable My Location
then set your default location, this can be a whole city
or you can refine it down to a town
you can of course go down to whatever level of detail you want for the default location for your posts. I would suggest keeping it quite broad as this is where any post you don’t geolocate when posting will be placed by default.
Click save to apply the geolocation settings and you are now good to go.