A bill of sale artists present to the client which lists the services (typically licenses) being sold & for what amount. Should include a signed grant of reproduction rights & the artist’s social security number or artist’s business Employee Identification Number, as well as the artist’s mailing address.
Best practice includes adding the clause “All rights not expressly granted are reserved to the artist. If payment is not received within 30 days of invoice date, a 15% additional fee will accrue. If client wishes to make any additional uses of the work, client shall seek permission from the artist and pay an additional fee.”