The invoice date indicates when the purchase took place. It assists businesses in keeping a record. If there is any misunderstanding regarding when a product is bought, the invoice can be referred to. It is also used as a record of authenticity and balancing the financial statements. One can usually find the invoice date at the top of the invoice, either on the right or left side. When an invoice is being filled, the first thing that people usually do is put in a date so it can be looked back at whenever necessary.