What exactly does an advertiser do?

Answer 1

An advertiser mainly concerned with displaying an ad in form of text, image or mix of them at a specific place where he have to pay to display his ad. Google adwords is one place of places where you can advertise your business, product or services.

Answer 2

An advertiser creates and executes marketing campaigns to promote a product or service. They identify target audiences, choose appropriate advertising channels, and create compelling messaging to drive consumer interest and sales. Advertisers also analyze campaign performance to optimize future strategies.