When I try to use underscore in my post, sometimes the preview displays my text in italics with no underscore. That confused me, and I have placed two underscores. Now the preview does not show the actual preview. For example, if I add underscore before the text, the text displayed normal text enclosed by a single star. (i.e. BOLD _italic italic)

However, I don't know how to use * in my text if it is used to define italic text. (i.e. *ABC). How do I use underscores and asterisks in the Stack Exchange editor literally?