Maintenance fund invoices are usually rectangular receipts with a length of about 20 cm and a width of 10 cm. The receipt is stamped with the seal of the house maintenance fund management center where the property is located. This is a receipt in duplicate. Among them, the housing maintenance fund management center, the real estate management department, the owner and so on each keep the corresponding vouchers. This kind of invoice is used to record and prove the maintenance fund paid by the owner and the use of the maintenance fund.