To display the product code only on the invoice preview (and not on the printout) you can hide it using a CSS code.
To achieve this, go to Settings> Account Settings> Print settings, and then at the bottom of the page, in the Customize print with CSS field, use the following CSS code:
}
@media print {
.main_inv_table > thead > tr > th:nth-child(3),
.main_inv_table > tbody > tr > td:nth-child(3) {
display:none;
}
}
Note. The product code will not be shown on PDF or on the printout. However, when you provide the client with a preview of the invoice - the product number will be visible in the invoice HTML code