Odoo customization

We need customize Odoo. 1. Create in the POS configuration in the Invoices and receipts section two fields called document type and document type id. Add the field called "Doc Type Json". And this used in Json Web Service. The WS is created. 2. Create in the POS configuration in the Invoices and receipts section two fields called area_id and cost_center_id. 3. Include POS Offline Customers module in our environment. We have the module [login to view URL] the NIF Validation. The algorithm is: [login to view URL] 5. Modify JSON to integrate for include fields: cost_center_id, área_id, document_type_id. The WS is created. [login to view URL] the invoice pdf (in WebPOS) to include Access code (field existing) in the header. 7. The fields Product ID (WS) and Customer Tax ID in Product Window is required. Validate this fields.