1. Open the Invoices menu.
2. In the Invoices module, select the Settings -> Account settings menu.
3. Open the Documents numbering section.
4. Select the Default format of invoice numbering by using the field --select from examples--. Repeat this action for:
- The default numbering format Proforma,
- Numbering format of Credit Notes,
- Default format of bill numbering.
5. Save changes.
