You cannot change the invoice numbering completely but you can set the prefix on your invoice numbers:
- Go to 'Your Profile' at the top right
- Select 'Company Settings'
- Scroll down to the 'Auto Numbering' section
- In the 'Select an Object' field, choose 'Invoice'
- In the 'Prefix' field, you can add your unique job using a - to separate the prefix.
Please note that the prefix will appear on your finalised invoice and not the draft invoice.
Please note that it is the user's responsibility to ensure that all invoices and credit notes issued to customers are compliant with HMRC’s rules on the issuance of invoices and credit notes. For more information, and to familiarise yourself with the latest advice, please refer to the government’s website.