Setting up invoice series

Invoice series control the numbering of your invoices. Go to Settings > Invoice Series and create at least one series with a prefix (e.g., 'A' or '2026-A'). Each series auto-increments sequentially (2026-A-001, 2026-A-002, etc.). Spanish law requires sequential numbering with no gaps. You can create multiple series for different types of invoices — for example, 'A' for ordinary invoices and 'R' for credit notes. Set one series as default for convenience.