Caching is usually an issue with the visitor's browser. Sometimes they won't get a change that you have made to a page. So a Ctrl+F5 will force a reload of everything.
If you have enabled caching on the back-end (usually with a plugin), then you may need to rebuild the cache for that page. If you see the black admin bar at the top when you view the page, you might see a menu choice for "Cache" that will allow you to rebuild the site cache for that page.
If you have a 'cloud-based' site, then pages will be cached there, and a change that you make may not be visible until you clear the cache on your site.
If you are doing development work, then a theme code change, for example, may not show up, so you might have to force a full reload on your browser (Ctrl+F5), or perhaps rebuild that page's cache as described above.
Note that it always useful here to provide as much information about you problem as you can: the things you did, the way you did it, the outcome you expected, and the outcome you got (including any error messages). Adding this detailed information will ensure that you get a good answer.