The custom output lets you set the dimensions of the file which are ready to print. Enter the value for custom height and custom width in pixels for the output of your print file.
To set a custom output go to Catalog ➤ Products, you will land on the “Products” page. Now open the product in the “Edit” mode or click “Add Product” and scroll down to the “Product Designer” section.
Fill the Following Fields
Custom Output Width: Enter the custom output width for the print-ready file in pixels.
Custom Output Height: Enter the custom output height for the print-ready file in pixels.
After filling in all the information click on the “Save” button to save for your product