This is actually a CSS question. But it is hard to give an answer, since we don’t see the source code that creates the page. (And it could be a plugin or theme issue, and we don’t know that either.)
If it is a page created by a theme or plugin, then you need to contact the theme or plugin support site; that’s not a question for this place.
It may be as simple as changing a CSS style (which you could see by using your browser’s Development tools, or looking at the generated page code), but again, not enough information to give a definitive answer.