Accepting that copyright and copywriting are entirely different subjects, if you are looking to understand copyright, take a look here for a starting point. Copyright law varies between countries (in those that have it), so make sure you do some research for whatever country you are operating from. Taking the UK and the US as examples, the law differs between the two but copyright of an original work (and it does have to be your own original work) is automatic at the time of production of the work. In the US, I believe you can register a work for a fee, whereas in the UK, no such official register exists. Whether or not an official register exists or not, copyright applies in favour of the author from the date of production.
According to the US law, you have to register it to a copyright publisher / company. If you paste and put your name and date under it, even that is copywrite. However, copyright company ensures you are legally safe. It may cost you $200 for a bundle of articles.
I'm using Myfreecopyrights.com for my blog, and content gets copyrighted. Even if anyone uses your content, you can file complaint to DMCA with relevant materials.