Always get receipts or other vouchers when you buy something for your business.
The receipts have to show:
Sometimes, however, suppliers may not provide receipts. In this case, write the information in your records. Show the name and address of the supplier, the date you made the payment, the amount you paid, and the details of the transaction.
Make sure the seller describes the item on the receipt. However, sometimes there is no description on the receipt, as with a cash register tape. In this case, you should write what the item is on the receipt or in your expense journal.
Here is an example of how to record your expenses.