Competition is the force that most free-market economies rely on to make sure that businesses satisfy consumer wants and needs. All it really means is that buyers have choices. These buyers, of course, may be other enterprises or individual consumers. Whether we consider an oil refinery buying crude oil, a chain of petrol stations buying petrol, or an individual driver needing to refill his tank, if these buyers have choices among different suppliers, it is much more likely that they will get high-quality products at reasonable prices. The idea is fairly simple, really.
Consumers have money and want to spend it to satisfy their wants and needs.
Then we stand out of the way and let competition in the market operate. In most markets, most of the time, this is just about all the government regulation necessary to ensure that buyers are well served. Competition among suppliers to sell to customers will keep prices down. If suppliers can sell to more buyers and earn more profits by taking actions to lower their costs, they will do so. Competition among firms forces them to be more progressive than their rivals to attract buyers.