It's easy to change the font size for your packing slip; it just requires that you copy and paste a few lines of code into your packing slip template(s).
*Please note that you need to be on a Silver or higher plan to customize your packing slips.
Head to your Account Settings (the gear icon in the upper right).
Next, select Templates and then Packing Slips from the sidebar on the left.
On this screen, you'll see a current list of your packing slip templates.
Either copy or edit an existing template, and the Order Header section should open by default. Simply add the following code to the very top of the Order Header to make the font bigger (12px is the default for 8.5x11 formats):
Feel free to adjust the font size number to match your preferences. You're able to download a sample, but don't forget to click Save when you're done editing. Now, you have a customized packing slip you can send to your customers for each of your stores!