Your instructor usually determines which style guide he or she wants you to use in your papers. If you don't know--ASK THEM!
Information on a variety of styles is available on the Libraries' Writing Style Guides page.
Quick Citation Formatting in Databases. Many databases allow you to format citations into various writing styles. When available, look for the wording “cite” or “cite now,” or see if it is an option after clicking on “save, print, email.”