A crown is generally used to cover a damaged tooth, while veneers are thin pieces of porcelain that work to recreate the natural look of teeth.
Dental crowns are placed on top of the tooth completely to improve the appearance and shape. They're also used to be placed on top of dental implants for missing teeth and gaps.
Veneers are used to improve the look of teeth while also making them stronger. Veneers do not go on the entire tooth like crowns, but are fitted to make slight alterations like changing tooth shape and size.