Hi,
The address information area on the registration form is displayed using the data of the custom address fields that you configured in the menu Display>Custom fields.
So if you want to add / remove / change the fields there, I would first recommend to look at their settings in that menu of the HikaShop backend.
Then, if you want to go deeper with the customization, you can edit the file user / custom_fields.php via the menu Display>Views. To know which view file to edit, you have the "Display view files" setting in the HikaShop configuration that you can activate. Then, just refresh the page you want to modify and HikaShop will tell you which view file is used where, as per this tutorial:
www.hikashop.com/support/documentation/1...-display.html#layout