Start with the business need
Procure-to-pay (P2P) connects a requirement to the eventual payment of the supplier. Materials Management runs the logistics side — requirement, order, receipt, invoice check — while Financial Accounting owns the payable and the payment. Most P2P problems happen at the hand-offs between the two.
Follow the documents
- Purchase requisition (ME51N, or created by MRP) — the internal request.
- Purchase order (ME21N) — the legal commitment to a supplier, with price, quantity, date and tax code.
- Goods receipt (MIGO, movement type 101) — stock increases; Finance sees inventory debit and GR/IR credit.
- Invoice receipt (MIRO) — GR/IR is debited, the supplier account credited, and differences checked against tolerances.
- Payment (F110) — Finance clears the open item when it is due and not blocked.
All of it is visible in the PO history tab of ME23N — the single screen every MM consultant should be fluent in.
An example to think through
An order requests 100 units at ₹50. Only 80 arrive. The supplier invoices 100. With GR-based invoice verification, MIRO proposes 80; if the clerk enters 100, the quantity variance exceeds tolerance and the invoice is blocked for payment (block R). The document trail — PO, GR, IR — tells everyone exactly why.
Where P2P breaks in real projects
- Missing or expired info-record prices → POs without a price.
- Wrong GR-based IV flag → invoices that cannot be matched to partial deliveries.
- Unreconciled GR/IR at month-end → Finance escalations.
- Approval bottlenecks in release strategy or flexible workflow.
Takeaway
Invoice posting and payment are separate events. Follow both the physical movement and its financial consequence, and P2P stops being a list of transactions and becomes one story.
A concept overview with illustrative examples. Exact steps and available functions depend on your SAP release and configuration.