What is an invoice?
What is an invoice and what to include in one. The simplest definition is that an invoice is a demand for payment. It's a document that's issued to your customer after the sale of goods or services. It includes details of what goods have been provided or work done, with subtotals for each section and a final total which is the amount that the customer must pay. An invoice is also a point of contact with your customers. Whenever you send an invoice, you tell your customers something about your business. By invoicing in a professional manner, you give the impression that you run a professional business. Invoices can be used to bill for one-off projects or for recurring work. They are most widely used to request payment after work is completed, especially where there is an ongoing relationship with the customer. Invoices used to be sent in the post, on paper, but that's now far less common. Emailed documents  often in PDF form  are more popular, but some companies now use e-invoices sent from specialist accounting/invoicing software. These have several advantages, the main one being that they help you get paid faster. All invoices should contain the following information to help ensure that they are processed properly and paid on time.