If you are printing thermal labels on an Apple computer, you likely must create a 4″ x 6″ custom paper size then set it as the default size for your computer. In order to do this, please follow the below steps.
First go to Safari, click on File and then Print…,
You should now see a Print window display. If you see a window such as the following, click on the Show Details button on the lower-left side of the window,
Then click on the Page Size button and choose Manage Custom Sizes from the drop-down,
On the Custom Paper Sizes window, click the ‘+’ button,
Then, you will get an Untitled template on the list. You can click and edit the name to what you prefer and then set the size of the paper to 4 in width and 6 in height. Make sure that the margins are set to 0,
As soon as you’re finished with the above settins, simply click on OK at the bottom. You can then exit out of Adobe and go back to System Preferences, the Print & Scan section. Here, click the Default Paper Size drop down menu and choose the custom label that you created.
That’s it. Your custom paper size will now automatically apply to all print jobs sent from your Appath account or any other application for that matter.