osCommerce adjustments

We added a custom Field in the user data. The field is called UID (Tax ID). When filling out it should be a required field. Six stings required. List of countries (user profile) should be limited to 3 (DE-AT-CH) The text shown as posting Type is 'MultiGeoZone MultiTable2 (4.3 lbs)' it should be 'Postversand' Delete the payment option 'cash on delivery' Erase Discount-Table Where can I edit the Mail-Text-Content sent to the buyer after purchase