No matter what you write, you can find a place for it online. Depending on what you want to do with your writing, there a few different ways to start your career. For instance, someone looking for advanced critique should go to a site like Deviant Art, while someone looking to make money should choose Bukisa, Helium or Triond.

Now, when you say that you want to write online, you need to be specific. What do you want to write? Freelancing? Creative writing? Here are a few sites that should help you out

Creative Writing – Deviant Art, Helium (will accept them), Storymash, Wattpad

Freelancing – Helium (marketplace), WritersWeekly, Freelancewriting.com

Articles – Triond, Bukisa, Redgage

Now, many of these sites will also pay you some of the ad revenue that is generated, or for the article itself. Either way, those sites will allow you to get started writing online.

A few tips to get you started

• Make sure that you state something new in every sentence
• Quality over quantity 
• Make friends so people can see your work
• Promote, promote, promote
• Aim for 800 words minimum if you’re selling your work
• Write what you know

Using more than one site is a good way to get recognized more, though keep in mind that some sites require that your writing is exclusive. The best of luck, and keep trying even if you fail. All writers get rejected in the beginning. The successful ones keep submitting.