Citation managers are tools that help you cite and organize the sources you find through your research. Though they may vary in their features, at their core they can help you cite your sources correctly based on the latest editions of the appropriate citation styles. Citation managers are great time savers in that a well-organized list of sources can be turned into a bibliography almost instantly, saving you precious time at the end of your paper.
While many citation managers like EndNote and RefWorks are expensive for individual licenses, there are other options out there which do many of the same functions for free.
Not so fast! Machine-produced bibliographies and citations are seldom perfect. You need to know how citation works and what your style should look like, even if you're using a citation manager -- if only so you can check that its work is correct!