If the ‘Orders’ object is enabled from the CRM, the customer can access and get the added orders list.
If the ‘Product’ selection is also enabled, at the time of adding/editing the Orders, the user will get the product selection sub gird.
The product list will be fetched based on the selection of ‘Price List’.
Similarly, the customers will get the Opportunity object and the Product selection in the sub-grid if you have enabled from the Object Access Setting on the CRM side.