When you click on the sale menu as shown in the image below, you will see a page where sale form is displayed as shown in the 2nd image.

In the sale form you will need to select the items from the item field one by one and add into the invoice by clicking on “Add to Bill” button.

When you select an item, it will fetch and display the sale price and available stock of the item. It will show 1 quantity(Qty) by default, you can change that any time.

If you don’t select an item from the list and add a new item, it will automatically add a new item into the invoice as well as into the system to display in the list in future.