An invoice is a binding document that serves as proof of a business for tax purposes. However, not all bills are equal. According to its functions, there are three different types of bills. Among them, the most commonly used bill is definitely the ordinary invoice.
An ordinary invoice is a document used to record a financial transaction, be it a sale or providing a service. Such invoice must contain all necessary information about this transaction.
This ordinary invoice, which is often called simply bill, is frequently used as the other types of invoice only serve the function of amend or streamline their procedure. In other words, the other bills are always issued in this function.