Hello,
Four possibilities:
Disable the cache in Joomla configuration. Site -> global configuration -> system -> "Cache settings". If enabled, please disable the joomla cache plugin.
Check your template' options for a potential cache option and deactivate it.
Some hosting companies use caching proxies like Varnish or CDNs which can potentially be configured to cache your pages. So please contact your hosting company to see with them if they do for your website/server and if it can be deactivated.
Thank you.