A purchase order is a commitment
An approved purchase order documents what you intend to buy. It does not by itself mean the goods have arrived or that a supplier liability is recognised.
Record a goods receipt when stock arrives
A receipt records the physical quantities accepted into a warehouse. It can happen before the supplier bill, so stock availability reflects the actual delivery rather than waiting for invoice processing.
Match the bill to the order and receipt
Compare ordered, received and billed quantities and prices. Investigate overages, shortages, damaged goods and price changes against the agreed tolerance before posting a bill.
Correct mistakes with traceable reversals
Use the supported reversal or correction workflow for an incorrectly recorded receipt or return, with a reason and retained history. An adjustment should explain a counted difference and should not be used to hide an unresolved supplier discrepancy. Inventory costing and tax accounting need separate policy review.
Examples are illustrative, not tax or legal advice. Your accounting policies and local requirements may change the treatment.