Invoicing guides: mandatory fields, small business, reverse charge, reminders

Writing invoices

The basics: what has to be on an invoice for it to hold up?

The complete checklist of every mandatory field under §14 UStG and §11 öUStG — including small-amount invoices and the most common mistakes.

When no VAT is shown on the invoice — and who owes it instead.

Invoicing without VAT: the correct §19 UStG note and the current turnover thresholds.

The recipient-liability mechanism under §13b UStG, explained simply — including the §19 trap between Germany and Austria.

What to do when an invoice goes overdue.

Reminder or Mahnung? When default begins (§286 BGB), how high default interest is (§288 BGB), and the usual escalation process.