Below you can see the details about each option available.
Default country shows in submit form and admin – add property. It is used to find the property location latitude and longitude when clicking on the button Pin Address on the Map.
Default Measurement Unit
For property site and property lot size default measurement
Language for the date picker
The date picker is used for custom field type date. This field, when added, will show in submitting the form (in the front end), submit the form (in admin) or an advanced search (if the field is added in there as well).
The language is applied for the months in date-picker.
Google Analytics ID
Copy the ID from your google analytics account and sync your site with analytics for details analytics of your site visitors). https://analytics.google.com/analytics/web/provision/?authuser=0#provision/SignUp/