Please make sure you are in the Classic Interface.
You will need a Experian Address Validation Licence and purchased geocoding to be able to use this function.
This optional functionality will give end users an extra level of detail on validated address data. The Latitude and Longitude fields will display the coordinates of each address. Add the Match level field to specify whether the address data pertains to a building, street, or postal code.
To enable the Latitude and Longitude fields:
From the main dashboard drop-down menu, click Settings, then Customizations.
Click Customize the System, which will bring up a new window.
In the left panel, expand Entities, then expand the entity you want to add the fields to (e.g. Account), and click Forms under the chosen entity.
Click on the form you want to add a field to (e.g. Account Quick Create), which will open a new window.
From the Field Explorer on the right-hand side, find the Address 1: Latitude and Address 1: Longitude fields and drag and drop them into the location you want on the form.
Select each field and click Change Properties from the top menu bar.
In the pop-up window, ensure the Visible by default box is checked in the display tab and click OK.
Click Save and then Publish.
You can now close the pop-up window to get back to the customization dashboard.