A proforma invoice is a document that is typically used to give potential buyers an estimated cost of goods or services. The proforma invoice can be used as a binding contract if both parties agree to the terms and conditions listed on the document. The format of a proforma invoice can vary depending on the company, but it typically includes the company name and contact information, the date, a list of goods or services with a description and quantity, the unit price, the total price, shipping costs, and payment terms.