Last Name, First Name. Title of Book. City of Publication, Publisher, Publication Date.
Author(s). "Title of Article." Title of Journal, Volume, Issue, Year, pages.
Most articles found in library databases will be scholarly articles that should be cited in this format. If you find articles elsewhere, or aren't sure what kind of article you have, check the "MLA Citations for Periodicals" link above to help identify what you have.
It is a good idea to use a citation tool to help you with your citations. You can use either a citation generator or a citation management tool.
A good citation management tool is Zotero. More information can be found at this link.
A good citation generator is Zbib. Check out this quick tutorial about it.