If you have custom packing slip templates you'd like to add the ShipStation Scan to View barcode to, go to the Packing Slip Template in your template settings and add the following line of HTML to either the Order Header or the Order Footer section of the packing slip editor:
<p align="center"><barcode size="small">[Barcode]</barcode></p>
Of course, you can adjust the paragraph alignment and adjust the barcode size as needed.
You can use the following values for barcode sizes:
Requires Document Options!
For the barcode to appear on the packing slip, you must also have barcodes enabled in Document Options. Go to
Settings > Printing > Printing Setup, then click Document Options. Check the option Include"Scan to View" Barcode on Packing Slips.