Big business organizations take help of advertising agencies in spreading the word about their products and services. These advertising agencies vary in size and often specialize in specific field of advertising tasks.  Advertising agency performs a lot of functions including creating visuals, overseeing media buying and advertising campaign planning.
Planning and Managing Advertising Tasks
Advertising agency plan and execute advertising campaigns for their clients. In the campaign planning stage they include many procedures including
·         Outlining a budget,
·         Setting goals and identifying the prospective audience
·         Conducting market research.
After initial stage, managerial staff provides supervision for the project, whereas creative and account services are handled separately. The creative work of the campaign is handled by the Graphic artists, copywriters, web designers and film makers.

Creative Work
Creative agencies employ a range of staff to provide creative services to their clients. The creative team includes graphic designers, photographers and filmmakers that create eye-catching art work to compliment the written elements of the campaign.
Branding
The primary objective of an advertising agency is to establish a strong branding for clients through their campaigns. Branding refers to the message through which an audience associates with a company and its products or services. The effectiveness of an advertising agency can be measured when a brand is strongly recognizable, and sales are boost.
Marketing and PR Agency
Many advertising agencies handle complimentary services related to advertising campaigns, such as marketing and public relations. When an agency handle public relation services, they  make sure a communication take place between a brand and its public and it manages the types of messages that pass between a company, its public and other parties, such as employees and the media.
Some advertising agencies also handle marketing tasks, such as research, events, networking, and online outreach. Since marketing and advertising are interrelated; therefore, it is common for advertising agencies to handle a variety of marketing tasks.