If you have had some updates done to your site, but you are not seeing those changes on the live site, you could be experiencing a cache issue.
Your cache is where data is stored on your computer temporarily. We typically associate this with the images and data of the websites you visit after visiting them for the first time. On subsequent visits to those sites your browser loads this data from your computer instead of the internet, helping it load much faster for you. Unfortunately, this cache of data on your computer is not updated like the live content is, leaving you seeing old files.
Clearing your cache is essentially the act of deleting those local files from your computer so that the latest files from visited websites are re-downloaded, allowing you to see new updates.
Browsers include functions for deleting these files, but unfortunately the process varies from browser to browser. Below is a third party website with information about how to clear your cache based on which browser you may be using...