Tā zài císhàn chōujiǎng zhōng yíngdé le yī fú huà.
She won a painting in the charity raffle.
Tips
usage
抽奖 (chōujiǎng, draw a prize) is the general term — used for everything from Spring Festival office lotteries to mall promotions. Tag 慈善 (charity) in front to mark a fundraising raffle specifically.