Hi Sam,

The Reference field on the PO header was considered initially as an alternative index that could be used for linking to paper requisitions like when users have a Paper PO book in their truck cab's and needed to cross reference to an actual PO. We always used for cross reference before optional fields were available.

It is only 12 digits and if your tracking number is 12 or less then that would work but but I'm thinking that if this is a tracking number from UPS then you're looking at 18 digits. FEDEX is 12. And most ocean freight tracking would be more than 12.

But Optional Text fields work too, as Bruce has suggested.

Best,
Brian