In Halaxy, an invoice number is automatically assigned when you create an Invoice. However, you have the option of creating your own custom numbering. This allows you to keep track of your invoices based on your personal preferences or to keep your invoices consistent if you have imported them from another practice management software package.
To set up custom invoice numbering:
Click Settings > Payments.
In the Invoice Numbering section, click Edit.
The Edit Invoice Number Settings pop-up appears. Select "Custom invoice numbering".
(Optional) Add a prefix and suffix, and choose the next available invoice number. An example invoice number is displayed as a preview.
RESULT: New invoices will follow your new numbering. Note that previously created invoices will still have their old numbers. To change the invoice number of an existing invoice, see the Invoice Summary by clicking the cogwheel icon on any invoice. Please note that Halaxy will not allow two invoices to have the exact same ID, even for deleted invoices. If your custom numbering results in an invoice having a duplicate ID, that number will be skipped.