Copy DFF value on anothe form using Form Personalization

Hello Team

I got requirement where I need to copy the DFF values from PO lines form and need to insert/update into invoice lines form DFF.

This is related with ERS invoices , whenever any ERS invoices is generated in system, our DFF values should also get updated in invoice lines DFF (Invoice line DFF defined same as po line DFF).

We run pay on receipt standard programme by passing receipt number in it and it automatically triggers payable import and generates ERS invoice in system  against that PO receipt.

SO , how would I do this , I am not  so clear and want expert advise.