The "Customer & Billing" sidebar box displays customer contact and address information captured during checkout. Customer Name - Full name from checkout form (e.g., "John Smith") Email - Email address as a clickable mailto link for easy contact Billing Address - Complete address including street, city, state, zip, country formatted for readability Customer information is stored in post meta with dual support for both old and new key naming conventions: Field Meta Key (Preferred) Meta Key (Legacy) Type Customer Name _order_client_name _invoice_client_name String Email _order_client_email _invoice_client_email String (email) Billing Address (JSON) _order_billing_address N/A Array (serialized) Address Street _order_client_address N/A String City _order_client_city N/A String State/Province