Tracking sales of goods is easy in QuickBooks. Create a sales receipt or an invoice. Pick the product the customer requests along with the quantity and then save the transaction. QuickBooks will adjust the appropriate inventory level and record the purchase correctly. But when you account for services that you have sold, that can get complicated. When you need to charge your customers for labor, consulting, or any service and bill by the hour, it is necessary to set up records for billable time and also track hours spent on each task. Fortunately, both chores are made simple by QuickBooks.