In many cases, novel titles are italicized. It's a common formatting convention to make them stand out. However, it can also depend on the specific style guide being followed.
Typically, novel titles are not underlined. They are often presented in italics to distinguish them from the main text. However, the specific formatting can vary depending on the style guide or publishing requirements.
It varies. Some style guides say yes, short story titles should be italicized. Others might have different rules. For example, in academic writing, it could be different from creative writing.