To add additional columns like Discount and Comment in Item section while making PO, follow below steps:
[A] While making Purchase Order in Transactions Module, Click on "Optional Columns" as shown below.
[B] Once you click on the "Optional Columns" a drop-down list appears, you can select either the "Discount" Column or "Comments" columns or both.
[C] Once you select these, it will appear as a column in the Item section.
Keywords: Discount Columns, Comments Columns