Registration & Checkout form in Opencart

I need to make a custom form for the customer to register on my opencart based website. Also for the checkout part. I need the customer to first sing in with personal details: Name, Phone, Email, ID Number All of the mandatory. Then customer will have two buttons: Delivery Adress, and the other Invoice Data(only available for companies). For the delivery adress standard fields will Apply - Adress(mandatory minimum 10 characters) - City(mandatory) - Area(judet)(mandatory) - Post Code(not mandatory -Country(mandatory - dropdown) For invoice data i will need the following fields. - Company Name(mandatory) - VAT registration number(CUI)(mandatory) - Account No(not mandatory) - Bank (not mandatory) In the account part of open cart, customer will be able to change, add another delivery adress and another invoice data. Also the delivery adress will appear in admin and on the invoice under delivery adress. Same for invoice data. If invoice data is selected the under the box payment_adress in admin it will apear the invoice data. If no invoice data is selected the personal details will be used. Any questions you might have please free to ask