Create new/custom PO Header or Item Text in Public Cloud

Dear Experts

Can idiosyncratic counsel however to adhd a customized PO substance tract truthful that it volition beryllium reflected successful the assorted PO Fiori apps?  Do we person to adhd them arsenic customized fields via Extensibility (e.g. Custom Fields & Logic app).  The PO volition not beryllium printed arsenic it is replicated from different outer strategy and the PO information is lone store successful the Public Cloud for notation purpose.

Thank you.