Once you have your boxes ready to go, you can print out shipping labels. Using the Edit order screen, you have the opportunity to print out a shipping label, as seen here:
This is powered by WooCommerce Services, so you have to have this plugin installed and activated to see this button.
You'll be asked to confirm your Origin address and the Destination address. Then, you can select packages and add a weight (if necessary), as shown here:
Click Use these packages, and then you can select your rate, as shown in the following image:
Finally, you can select Buy & Print. You'll get a PDF file, and you can print it out on your printer at home.
If you happen to have a label printer, you can change the Paper size field, and select a smaller size that will work with a label printer.