There are three common citation styles used in the college setting. They were designed for different disciplines and so they look a little bit different because those disciplines value different pieces of information differently.
There are examples of what citations look like in each of these styles using common source types in the column on the left side of this page.
There are as many citation styles as there are journals and professions (or maybe even more). Depending on your course of study your discipline may use a different, specialized style. Below are some of the more common ones. If you are using one of these styles and need help with your citations, the style manual can help you get started: