# Invoice attachments and service descriptions

Use this checklist when timesheets, delivery notes, service reports, or construction details support an invoice that still needs structured required facts.

## What this means

Attachments can support a structured e-invoice, but they should not replace invoice facts that the XML must carry. If the buyer or validator needs a legally required field, put it in the reviewed invoice data before export.

Use this playbook for timesheets, delivery notes, construction specifications, service reports, and other documents that explain the invoice.

## Put these facts in structured data

- Seller, buyer, invoice number, issue date, currency, line amounts, VAT categories, totals, payment terms, and recipient references.
- A clear service or delivery description for each billed line when the invoice depends on that description.
- Delivery or service period when it is required for the transaction or recipient workflow.
- Discounts, charges, deposits, and references that change the payable amount.

## What an attachment can carry

- Detailed timesheet rows that break down a line already described in the XML.
- Delivery notes, acceptance sheets, or service reports that support a structured line item.
- Construction specifications or bill-of-quantities detail when the structured invoice points to the attached document clearly.
- Extra context for a reviewer, as long as mandatory invoice facts still exist in structured fields.

## Before export or API retry

- Check whether any attachment contains facts missing from the review form.
- Move required facts into the invoice fields instead of leaving them only in a PDF attachment.
- Keep attachment references specific, such as a delivery note number, service period, or contract reference.
- Run validation after corrections and compare the exported artifact with the reviewed invoice data.

## Official reference

- [BMF FAQ on mandatory e-invoicing](https://www.bundesfinanzministerium.de/Content/DE/FAQ/e-rechnung.html): The German FAQ explains when mandatory invoice facts need to be in the structured part and when supplemental attachments can help.

- convert
- validate
- api