Hello @simonfauci 

Please check these two online help content

2.12.7.1 Match Supplier Invoice with Purchase Order (ifs.com)

https://docs.ifs.com/ifsclouddocs/24r1/SupplierInvoicing/ProcessSubMatchSuppInvPurchOrd.htm

They do give the details for each one. Have added some thoughts below on when to use each one ( though majority of the answer, is usually within the organization based on the Accounting / Costing policies) based on which a setup is done to use these options.

1. Match PO Receipts -  In this case, the Supplier invoices one cumulative line , for one or more receipts, and the total value of the invoice matches the total of the deliveries done. This option is chosen when the accounting is cumulatively for all the lines together. Normally in such cases, the charges are usually at the header level in the PO ( if any ).  These could essentially be for parts or services, or a combination, which is provided under a Fixed Price contract, as one example. This could also be used for parts only delivery, and invoiced cumulatively.  In this case, if using the external invoice template to load the supplier invoice, we can use the “A” record type.
2. Match PO Receipts per line - In this case, supplier invoice contains separate lines for each deliverable. The company paying , may be accounting and costing these separately , and hence advised the supplier to send separate invoice lines, for each such delivered service. In this case too, system allows to have one or more receipts, with the totals matching for invoice line vs the total receipts for that invoice line.   In this case, if using the external invoice template to load the supplier invoice, we have to use the “HIPT” record types, for each record line, as well as provide the receipt reference, in the supplier invoice, to identify the receipt lines, linked to each supplier invoice line.
3. Match PO receipts per Part -  This is an additional option within IFS, and used essentially when costing per part, is required to be accurate. When purchasing parts, the matching functionality helps you control that only parts that actually have arrived are matched and that the expense postings for these parts are always connected to individual invoice lines. When renting in assets from suppliers this functionality helps you to invoice the already generated rental transactions. It also prevents you from paying for the same parts twice, or paying for returned goods. This special matching activity is used to perform an automatic matching between specific purchase order receipts and supplier invoice lines. The automatic matching is started manually for a specific invoice at a time. The matching of purchase order receipts and invoice lines is made by order number and purchase part number or charge type. ( as copied from the help content above ).