Why the changes are displayed in preview but are not visible in my published website?

All changes are instantly applied to a published webpage the moment you publish it. If you are seeing an old version of a page, it means your browser is showing a saved version from a cache. Reload a page ("F5" for Windows, "Cmd + R" for Mac) to see the changes.If a simple reload does not help, you need to clear your browser cache.To clear cache in Google Chrome:Open Chrome on your desktop.Click the menu button  in the upper right corner.More Tools → Clear Browsing Data.On top, select the time range. To delete all the data cached, select "All time".Select the "Cookies and other site data" and "Cached images and files" tick boxes.Click "Clear Data".