Use your browser's developer tool to check the response header for the HTML file. This can usually be done by right clicking on the page and selecting some form of “Inspect”. Then click on the “Network” tab in the inspector and reload the page. If you see “X-LiteSpeed-Cache: hit,litemage” in the response header for the HTML file(usually listed first), then the page is being served by LiteMage Cache.
Also if you see “esi:include” in html (Elements section in development tools), it means your server does not have LiteMage feature enabled hence ESI directives are not being processed.