How to modify print area: rectangular shape?
To modify rectangular print area.
2. Go to Products in the toolbar towards the left and select Product List from the drop down.
3. The product list will appear towards the right. Select your product.
4. In the product page, click Boundary located under Boundary.
5. A box will appear. Go to Variable Boundary and tap Configure Custom Boundary.
6. A popup named Configure Custom Size will open. Go to your selectd size and modify properties, such as name, height, and width.

7. Once done, click Update to save your changes.
8. Close the popup.
You have modified rectangular print area.