How to customize the "Select and Add" page (Create Invoice from Supplier portal) with page composer

How to customize the "Select and Add" Pop up page (Create Invoice from Supplier portal) with page composer.

Requirement is to Hide the Purchase Orders Lines with Unit Price Equal to Zero.

We are not able to edit that field in Page composer-Structure page

Is there any way to make the pop-up editable and updatable via Sandbox?

Thank you