Need an editable non mandatory DFF on Selected schedule payments page

Hi Team,

Our users in Italy in order to comply to the below law wants to have a field or DFF to capture CIG .

New Law in Italy Requires CIG code via CIG Law - Dlgs 66/2014 art. 25 CM2

To explain :

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Generally when we submit a PPR post entering selection scheduled criteria from Payments manager , the system selects the eligible invoices captured in the table AP_SELECTED_INVOICES_ALL and the status of the PPR becomes "Invoices Pending Review".

So at this statge when we click the button "Start Action" we can see the invoices which are selected as per the below screenshot.