You may have received multiple separate orders from a single customer and are wanting to combine all of those orders into a single shipment.
To combine these orders, open up your Orders page (Create -> Outbound & Export -> Orders), and select the orders you wish to combine by ticking the checkboxes. Once you have checked all the orders you want to combine for a single order, scroll to the bottom of the Orders page and press the 'Combine Ship Selected' button.
This will use the first selected address (of those orders) for the receiver section and mark all selected orders as processed once you print the label.