No, invoices are not usually legally binding agreements on their own because they do not contain the element of agreement a contract provides. The customer doesn’t sign the invoice. They either pay it or contest it. For this reason, invoices are not legal documents in their own right. However, invoices can be annulled by a credit document if they are created incorrectly. It is best to think of invoices as partners with your contract. After the contract has been signed, invoices are created based on the terms of the contract. See how Indy’s Contracts tool can help with that.