No need. According to the information of official website, China Taxation Bureau, if the sales of operators do not meet the prescribed standards (generally, the annual sales do not exceed the limit) and are not registered, they can be exempted from VAT and do not need to issue invoices. Selling vegetables is a small business, so they don't need to issue invoices. Enterprises or individual industrial and commercial households with sales reaching a certain scale need to issue invoices in accordance with regulations to ensure compliance with tax laws and regulations and provide customers with legal tax payment vouchers.