what is an invoice used for 
besides notifying a customer that payment is due it also serves as a paper trail for accounting purposes the bottom linean invoice is a document used to notify a customer that payment is due it also serves as a record for the issuing business so that it can track its receivables in the past invoices were only issued on paper due to the limitations of technology more recently electronic invoices become popular because they save time and money and can be generated and sent automatically 