Yes, you can backdate an appointment for invoice purposes by following these steps:
Edit Date of Service:
When marking the session complete in the appointment section, you can edit the date of service in the open tab.
Edit an Existing Invoice:
Navigate to the billing section.
Select the invoice you want to edit and click the “Edit” option.
In the edit screen, you can modify the line-item dates as needed.
You can also add or remove line items from the invoice.