If you're ever have a quantity for a single line item that is too large to fit in a single package, you can split this quantity. This allows you to create multiple labels for the same order.
For details, please take a look at our step by step guide.
How to: Add multiple packages to UPS and FedEx shipments
Can I combine orders after I’ve split them?
What happens to a category tag when an order is split or combined?
When an order is split, is a confirmation email sent when each part of the order ships?
Can I list fractional quantities of order line items?