i have one table quotation with portal in which item code is coming from product table,i want to copy all data from quotation along with portal records in to sell layout.

thanks in advance

You can share the line items table between the Quote and Invoice tables. Simply add a InvoiceID to the line items table. How you populate it is a matter of interface. If all items from a quote and assigned the same invoice, then you can simply place a "Create Invoice" button on the Quote form. This button would create a new invoice, capture its ID and populate the Quote's line items with that Invoice ID.