> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.invoice123.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# How to Assign Invoice Series Automatically?

When creating an invoice or VAT invoice and converting it to an advance invoice or credit VAT invoice, the series included in the settings can be automatically assigned according to the changes made. 
  
### How to do this?

1. Select **SETTINGS** from the menu bar
![](https://storage.crisp.chat/users/helpdesk/website/a9835b72ea0f8000/settings_fnfguz.png)
2. Select **SERIAL AND REFERENCE NUMBER** in the sidebar
![](https://storage.crisp.chat/users/helpdesk/website/a9835b72ea0f8000/serial_cin867.png)
3. Select **ADD ADDITIONAL REFERENCE NUMBER**
![](https://storage.crisp.chat/users/helpdesk/website/a9835b72ea0f8000/screenshot-2024-05-29-at-14533_k7pnw7.png)
4. Select **ADD ADDITIONAL DOCUMENT**
![](https://storage.crisp.chat/users/helpdesk/website/a9835b72ea0f8000/screenshot-2024-05-29-at-15150_1wnlgv6.png)
5. Link the document from the list and select the series type, click **DISK ICON**
![](https://storage.crisp.chat/users/helpdesk/website/a9835b72ea0f8000/screenshot-2024-05-29-at-15152_12n4psp.png)
||| Don't forget to save your actions by clicking **SAVE CHANGES**