What is your use case?

Are the customer order lines related inventory sales parts or non-inventory sales parts? 

@Sanjay.K There is no mandatory requirement to use the Shipment object to process a Customer Order (CO). It is possible process a CO without a Shipment. Or it is possible to get the CO line connected to a shipment automatically when the CO is released or when a Pick List is created.

The parameter Shipment Creation in Shipment section in Order Detail tab in the Customer Order can be used for this purpose.

Alternatively, the Shipment Creating Method parameter can also be used  in the Customer Order line.

When this parameter set to Not Automatic, the CO Line will not be automatically connected to a Shipment. However the CO line can still be connected to a Shipment, manually, if it is required.

Hope this helps !