I need to be able to bill a single purchase order multiple times, when testing I only have the "bill" button once, and after it's selected it no longer shows. Is there a way within NetSuite to receive and record multiple invoices for a single purchase order? Thanks

are you meaning items or expenses PO?

Expenses.

Expenses lines have an underlying Qty of 1 so are fulfilled and billed in full. Your PO could have multiple lines and Bill one line each time.