Rather than simply handing off the art and collecting money, it is best that artists create invoices for each sale to not only keep track of customer information and the money they're making, but to protect themselves in the event of a payment dispute. Copies of paid invoices will also be necessary when filing annual income tax. Creating an artwork invoice is fairly straightforward and does not take much time.
Open a new document in a word processing program such as Microsoft Office Word or Open Office.
Place the phrase "Invoice" or "Bill of sale" at the top of the document in capitalised letters. You can centre this or justify it to the left or right of the page -- either is fine.
Type the following onto the word document, giving each section it's own line: "Date of sale," "Invoice no.," "Artist name," "Purchaser name," "Address," "City, county, postcode," "Phone," "Email," "Description of artwork," "Print price," "Frame price," "Delivery charges," "Total," "Signature of purchaser: Artwork received in good condition" and "Date of delivery."
Add a copyright statement onto the bottom of the invoice, if the work is not a commissioned piece and you plan to retain copyright and reproduction rights. For example, you can use the following phrase: "Reproduction rights and copyright reserved by artist."
Print out the invoice and fill in all applicable information, except for the signature section. If you prefer, you can type the information into the form instead. Make a copy for your records as well as one for the customer.
"Invoice no.," which is a number assigned to help keep your billing in order, and "Frame price," which is included if custom framing was made for the piece, are optional and only needed if they apply to the sale.