You record the supplier's invoice against the received delivery on the purchase order.
Open the purchase order and find the received delivery.
Click the tick icon on the delivery header. It only appears on a Received delivery with no invoice yet. The Add Invoice Number form opens.
Enter the supplier's invoice number in Invoice #.
Check the Date. It defaults to today.
Check Total VAT. It is pre-filled with the calculated tax. If the supplier's figure differs slightly because of rounding, type the supplier's figure. Omono stores the difference as a tax adjustment so the bill matches the invoice exactly.
Click the tick to save.
The delivery header now shows Invoice # and the number in place of the status dropdown. A note on the PO records who posted the invoice.
If the supplier will not issue an invoice, tick Invoice Unavailable instead and save. The delivery is left off the Outstanding Purchase Order Invoices report and is never sent to Xero. If the invoice arrives later, click the tick icon again, untick Invoice Unavailable, fill in the invoice details and save.
For every field, what invoicing locks, fixing mistakes and what is sent to Xero, see Supplier invoices.