1. Go to Setting > Invoice Customization. Click Document Numbering tab.
2. SimpanKira allows you to create your own Prefix for the following documents;
   1. Quote
   2. Sales Invoice
   3. Delivery Order
   4. Credit Note
   5. Receipt
   6. Purchase Order
   7. Purchase Invoice
   8. Payment Voucher
   9. Debit Note
   10. Fixed Asset
3. You can enter any combination of letter and number at Prefix input field.
4. Click at Save button once you finish working on the prefixes.