From Wikipedia:

Advertising is a form of communication used to encourage or persuade an audience (viewers, readers or listeners) to continue or take some new action. Most commonly, the desired result is to drive consumer behavior with respect to a commercial offering, although political and ideological advertising is also common. The purpose of advertising may also be to reassure employees or shareholders that a company is viable or successful. Advertising messages are usually paid for by sponsors and viewed via various traditional media; including mass media such as newspaper, magazines, television commercial, radio advertisement, outdoor advertising or direct mail; or new media such as websites and text messages.

Commercial advertisers often seek to generate increased consumption of their products or services through “Branding,” which involves the repetition of an image or product name in an effort to associate certain qualities with the brand in the minds of consumers. Non-commercial advertisers who spend money to advertise items other than a consumer product or service include political parties, interest groups, religious organizations and governmental agencies. Nonprofit organizations may rely on free modes of persuasion, such as a public service announcement (PSA).

Modern advertising developed with the rise of mass production in the late 19th and early 20th centuries.