From the left-hand navigation menu select Invoice menu item and then the Generate single Invoice sub menu item
Select the name of the customer and the date range for the Single Invoice. This will show all the appointments that have not been Invoiced yet
You can select all the line items or choose the appointments that you want to invoice for.
You can edit price of any line item by clicking on the pencil icon which will bring up the edit price form.
You can add custom lines to the invoice which can be additional surcharge or discounts for the Invoice.
Select buttons at the bottom of the page; if you want to create the Invoice in Draft Mode (can be edited later) or Finalized the Invoice.