12. How do I add a product on an estimate/invoice?

You can simply enter a new product directly in the new document form, providing a name, quantity, unit price and a tax. Then just press the Add button in the far right end. This will insert the product in a table below. You can repeat the steps above as many times as needed. The newly added products will be saved by the program when the document is saved away. Afterwards, all the newly added products will be available for selection in the products/services list.