We added an extra field to profile fields section. But we couldn't find this field in order table. Where extra fields are saved in database ?
It is saved in a numerically indexed array if you have specified that those fields are to be part of an order.
You will have to have code modifications to map those index values to names if you want to reference them by name.
Check the cscart_profile_fields_data table with the object_type = O and object_id = ORDER_ID