Please note: many library databases include citations in the individual results' records. If you click on the title of an article, there is often a suggested citation in that article record. Google Scholar also includes citations under a link called Cite, so you could search for an item you already have in Google Scholar and use its citation.
Citation Machine--This resource seems to default to APA style. There is also an MLA version.
Zoterobib--Before you start, verify the citation style setting in the blue box, then you can search for your article and make a citation that way or manually enter the information to make a citation.
It's a smart idea to copy the citation and paste it into Word as Text Only--an option under the Paste button--and then just get in the habit of putting certain words--titles, etc.--back into italics. That's much easier than pasting straight from the Internet into Word and then having to undo different web formatting for each citation.
It's also a smart idea to double-check the form of the citation against OWL.