If some of your orders require multiple boxes to ship, ShipStation includes the ability to create multipackage shipments for UPS & DHL Express.
Create a Multipackage Shipment
First, find the order for which you need to ship multiple packages and view it in the Order Details screen or the Order Sidebar on the right.
Next, choose a service from a supported carrier. Once the carrier is selected, you should see a "+" icon to the right of the Package drop-down menu.
Once you click that icon, a new window will open to allow you to add packages to the shipment. Any relevant weight and dimension details from the Order Details or Order Sidebar will be transferred into the first package of the Ship Multiple Packages window. To add more packages, simply click Add a Package.
Repeat the process of adding packages until you’ve created all the component packages needed for the shipment. The weights you enter for each package will automatically add together when you view the order on the Order Detail screen or in the Order Sidebar.
*If you'll be entering the same configuration of packages over and over, consider saving a package set before you click Save Changes.
The labels for multiple packages will print the same way they do for any other shipment, only there'll be more of them! Each individual package will have its own tracking number and label, but there will be a master tracking number that will track the combination of packages. The master tracking number is the one that will be sent to your marketplace and customer, and what you will see in the tracking column of your Shipments tab. You may wish to send an additional e-mail to your customers with the individual tracking numbers, but that's up to you to do outside of ShipStation.