The customer's authorization document for specific work, with a number your invoice must reference. Many AP systems auto-reject invoices without a valid PO.
Why it matters before the job moves
Working without a PO number in hand means billing on hope. Confirm it before dispatch — it's a readiness check like any other.
Software for the boring operational stuff.SYNNR builds purpose-built software for oilfield service companies. Start with TallyShot — photograph a handwritten tally sheet, get clean Excel back.