Posting

That is typically a theme setting, meaning that it’s been written in to do that. Some themes specify that such information is displayed, others do not. If you’re code/css capable, you could edit your current theme, or you could try using something else.

Maybe someone else can instruct you on how to accomplish this in your current design, or you could contact the template/theme author directly.

Themes which support multi-authors will usually offer that feature.