Update customer PONum on Closed sales orders

Yes…
Here is a related topic that includes some of the common manuals (version names 10.1.6 shown )

Before attempting any modification, I recommend users read the two guides on “Tools” and “Customization”. They should provide 80% + of what you’ll need.

Also, it can pay to learn how to use the search on this site too.
Almost any question new users will have… were already asked/answered in prior topic(s).