That’s it! Not at all complicated, just a bit more hidden than you might expect from Apple.
The text will adjust its size as you change it, so you can stop when you’re happy with the size you like.
Each time you tap that button, the font size will increase by one pt.
On the far right side of the Size line you’ll see a ‘plus button’.
Change the Paper Size to either 30323 Shipping labels (2.13 x 3.97) or 30256 Shipping labels.
Select all of the text that you want to have a larger size font, and then tap the “Paintbrush” icon in the Pages Toolbar (see screenshot below). The only browser we support for DYMO printers is Firefox.