medical bills and invoices have different meanings and uses in the medical field. Medical bill refers to the receipt and payment voucher provided by medical institutions for patients, which is used to record the medical expenses and payment of patients. It is the original voucher of accounting, and it is also the basis for supervision and inspection by finance, health, social security, auditing and supervision departments. Medical bills usually include patients' personal information, medical items and expense details, and are used to apply for reimbursement of medical expenses and check the rationality of medical expenses. Invoice refers to the detailed sales voucher provided by merchants to buyers, which is used to record the sales situation and transaction amount of goods or services. The invoice usually includes the name of the merchant, the taxpayer identification number, the description of the goods or services, the unit price, quantity, amount and other information. Invoices play a role in confirming transactions, filing tax returns and safeguarding consumers' rights and interests in commercial transactions.