On-demand delivery is a service that allows customers to receive products or services at their convenience, often within a short time frame. This model is commonly used by companies like Uber Eats and DoorDash, where users can order food or groceries through an app and have them delivered quickly to their location. The process typically involves a customer placing an order through a mobile app or website, which is then processed by a nearby delivery person. This system has gained popularity due to its convenience, allowing people to access items without leaving their homes, especially during busy times or emergencies.