To get a free McDonald's coupon, you can participate in the McDVoice survey, an official online feedback platform for McDonald's customers. After making a purchase at a McDonald's restaurant, keep your receipt, which will contain a unique survey code. Visit mcdvoice.com survey, enter the code, and complete the short survey about your experience. Once you submit your feedback, you'll receive a coupon for a free menu item, typically valid for a limited time. This is a great way to enjoy a meal at McDonald's while providing valuable feedback to improve their service.