When adding an invoice, you have the freedom to create a service/type of product and add a price on the spot. Chances are, however, that you offer some services or goods at certain prices, with certain taxes applied to those prices.
If this is the case in your business, you will be greatly assisted in your invoicing if you utilize the "Items" functionality. It is essentially your inventory in Elorus. You can add a product manually or upload your list of products in bulk.
First of all, it enables you to search, choose and automatically fill-in product/service details in each item line of the invoices you issue. In the image below, the product is just selected from the list and the only field that changes is 'quantity'.
Moreover, by adding a product in your inventory you can activate automatic stock management: every time you enter a product in your Invoices, it will reduce the stock regarding the number of items sold. Similarly, whenever you purchase more stock - which is registered through Bills, this is added to your inventory in Elorus.
For every business, however, it is important that sales results of each product appear together, so you can compare. For products as well as services, you will have reporting that enables comparisons among sales of different products.