hi,
how can I customise an account receivable report which shows items for each invoice?
When asking about custom reports, you need to post the definition of your best attempt and show the result. There are also many topics on the forum where others have asked about this question. The short answer is that you cannot do it. And why would you want to? Receivables reports are generally used for collection management. And for that, it does not matter what a customer bought, but when they purchased and how much they owe. For this, the built-in Customer Statement (Unpaid Invoices) should be sufficient.