Invoice present before a check is produced
As a previous Stake Finance Clerk I always presented an invoice to another Church unit (Stake, Ward or Branch) calling for payment, I never made payment requests verbally.
Request from the Stake finance clerk an invoice, if you have exhausted your request for an invoice with no results generate/create your own expense detail with document preparation software (OpenOffice.org, notepad) or by hand and have your unit leader sign. When sending payment to another Church unit also fill out a donation slip and submit the white copy with the payment, and keep the yellow copy with your expense detail or invoice.
From another party you should have the invoice/bill present before a check is produced. And you should truly have an invoice present from the Stake before a check is produced.