Users can manually create their own number series by typing the invoice number in the Invoice #. 

1. Click on Invoice 
2. Click on the ‘+’ sign to generate a new invoice
3. Manually add invoice number in invoice #, e.g. Moon Invoice 1
4. Enter other invoice details and click on ‘Save.’

After creating an invoice series, all the upcoming invoices will be saved in the succeeding number—for example, Moon Invoice 2, Moon Invoice 3, and so on.