How to have Note to Supplier field at PO header and line level in iSupplier portal and PO PDFs (EBS

I am looking for the solution to have Note to Supplier field at PO header and line level in iSupplier portal and PO PDFs.

I need to assign this message to the items from 4 item categories. When PO with item from that list will be created, the Note to Supplier will be populated on PO PDFs and visible in iSupplier on item line and PO header.

What will be the easiest way to achieve it?

Thank you in advance for your help, It's kind of critical for me right now.