What do advertising companies mainly rely on to make money?

Generally, it is self-owned media, or media resources that represent others, such as LED screens in business districts, videos of building elevators, frame advertisements, outdoor brands of expressways, newspaper advertisements, magazine advertisements, TV advertisements and radio advertisements. If you have your own media, you will generally profit from the cost, and the agent media will generally earn the difference through contracting. There are many advertising companies on the Internet. Can communicate with the heads of advertising companies all over the country. I hope I can help you.