Invoice software is used to create, print, and send invoices to customers for payment. Typically, an invoice contains information such as the item quantity, product or service description, unit cost, and client billing address. Invoicing software with general ledger (GL) capabilities may also include a cash account and an accounts payable (AP) account. Some invoice software allows vendors to generate quotes and estimates. Other billing applications produce both standard and pro forma invoices. With integrated purchasing and accounting systems, vendor quotes can be converted to purchase orders. Estimates, however, may be time-limited. A standard invoice represents a bill-of-sale. A pro forma invoice or shipping invoice is provided prior to the shipment of merchandise. Invoice software for recurring invoices is also available. Invoice software differs in terms of features and capabilities. Basic turnkey products offer invoice templates, but may not provide integrated accounting, purchasing, and inventory management functions. More robust applications allow vendors to print, email or fax sales documents to customers. In addition to AP invoices, sales documents include credit notes, debit notes, delivery orders, and packing lists. Vendors issue credit notes to allow customers to purchase future products or services. Debit notes are issued to deduct funds from a customer’s account without a sales transaction. Delivery orders are shipping documents that release goods to another party. Packing lists or shipping lists provide an itemized list of a package’s contents, but do not include pricing information. Invoice software may support multiple tax rates as required by some states, provinces, and countries. Regional settings include currency types and symbols, as well as paper size. Invoice software that supports multi-business accounting allows users to create billing transactions for multiple divisions, departments, and other business entities. Reporting functions allow controllers, accountants, billing clerks and other AP personnel to track payments and overdue accounts. Sales managers may also review invoice-related reports. Some invoice software allows accounting personnel to apply a full or partial payment to a specific invoice. Other invoicing applications print reports about unpaid invoices, payments, item sales, and customer accounts. Web-based invoice software and billing software for operating systems such as Microsoft Windows is commonly available.