A freelancer is self-employed person offering services, usually to businesses and often to multiple clients at a time. The type of work freelancers do varies. Nearly every type of service a business would need could be provided by a freelancer, including (but not limited to), marketing, such as social media marketing, copywriting, and publicity, writing, such as articles and blog posts, technological support, such as web programming and design, creative works such as graphic design, and financial support, such as bookkeeping.
Freelancing is so flexible, you can set your own hours, working full or part-time on the projects of your choice. While clients can offer specifications to the work, a freelancer works similar to an independent contractor, in which he's free to control how the work is completed
Further, freelancing allows you to set your own price, which is often higher than what you'd make as an employee doing the same work.
The regularity of freelance work can vary. Many freelancers work for the same set of clients over a long period of time. For example, a freelance writer might have a client that requires an article twice a week ongoing.
Others work with clients over shorter periods, usually on specific projects. For example, a freelance web designer might build a website for a client and once the site is done, so is the work relationship.